Swampert & Sceptile
You BET I'm gonna bring these two up first. After all, Blaziken got a Mega, and he was already a very powerful Pokémon without it. It's completely unjust for the other two Hoenn starters to not receive the same treatment.
Mega Swampert
Type: Water/Ground
Ability: Bulletproof
HP: 100
Attack: 130
Defense: 120
Sp. Atk: 105
Sp. Def: 120
Speed: 60
This setup is more-or-less designed to make Swampert fill the same role(s) he already does, but with much greater efficiency. His defenses have received a solid boost of 30 points each, and his offenses have received respectable boost of 20 points each, which, combined with his awesome 100 base HP, makes him
very tanky. His Speed remains the same, but since it wasn't very high to begin with (and since many people like to run him with Curse), it would ultimately be pointless to increase it. To top it all off, he gains the Ability Bulletproof, which makes him immune to
ball & bomb moves (plus Searing Shot). This means he outright takes zero damage from his most common threat, the dreaded Energy Ball, as well as two other Grass-type attacks: Bullet Seed & Seed Bomb. There are other good coverage moves that he becomes immune to, as well, like Shadow Ball & Focus Blast, but those three are the most significant, as they will pretty much always OHKO him with his crippling dual weakness to Grass. Obviously there are still other Grass attacks that could be used against him (namely Grass Knot & Giga Drain), but having immunity to the most commonly-used one is a very good thing, and being immune to a select few other good moves only aids that. This all but makes him equally as metagame-dominant as he was back in his Gen III days, if not more so. This is one axlotl you wouldn't want to mess with.
Mega Sceptile
Type: Grass/Dragon
Ability: Adaptability
HP: 70
Attack: 105
Defense: 75
Sp. Atk: 125
Sp. Def: 95
Speed: 160
This setup makes Sceptile the fastest starter in the game once again -- and then some. His base 160 Speed (raised by 40 from 120) puts him a good 48 points above Greninja and ties him with Ninjask, the fastest non-Legendary to currently exist. This also makes him the fastest Mega, outspeeding Mega Alakazam and Mega Aerodactyl by 10 points. His other stat boosts are 20 points added to Attack & Special Attack, and 10 to Defense & Special Defense. He also gains the Dragon typing he was unrightfully jipped of so many years ago, giving him STAB for the Dragon moves he's capable of learning, as well as getting rid of his weakness to Fire -- though he also gains a weakness to Dragon and becomes 4x weak to Ice in the process, so there IS a drawback. That aside, though, his new typing & stats along with the Ability Adaptability, which increases his STAB from 1.5x to 2x, make him a dangerous threat. He still lacks the coverage to be a sweeper on par with the likes of Blaziken & Lucario, but he can definitely do more than hold his own, and he's easily capable of being a top-tier revenge killer -- just imagine his Leaf Storm! His classic SubSeed set is still available, as well, and given his ridiculous Speed & Adaptability-boosted Giga Drain, he's capable of abusing it more than any other Grass-type could even dream of. Of course, his durability is still pretty poor, so he certainly hasn't become invincible, especially with his dual Ice weakness, but regardless, he still maintains his already good versatility while receiving upgrades in all the necessary areas, so he's perfectly capable of wrecking an opponent's day.
The Johto Starters
While I'm not incredibly fond of the final forms of the starters from Gen II, I recognize that it only makes sense for them to receive Mega Evolutions in Gen VII. The Kanto starters got them in the generation where they (Mega Evos) were first introduced, so the natural progression is for the Johto starters to get them in the generation immediately following. For simplicity's sake, I'll go in order of how they're listed in the Pokédex.
Mega Meganium
Type: Grass
Ability: Regenerator
HP: 80
Attack: 92
Defense: 140
Sp. Atk: 93
Sp. Def: 140
Speed: 80
This setup is designed to make Meganium what could potentially be the game's greatest wall. It gives Meganium relatively large boosts in defenses (40 points each) and small ones in offenses (10 points each). The basic premise is to give Meganium defenses that are actually
good, while simultaneously giving it decent offenses as leftover stats to give it a little extra oomph in its attacks. The main star of the show, however, is the Ability Regenerator. This restores 33% of Meganium's max HP upon switching out, which is insanely useful for a wall. And, yes, this does make Meganium a much more effective Tangrowth. This is a good thing, though, as Tangrowth's Special Defense is pretty poor, making it extremely easy to take out with high-powered special sweepers, such as Greninja & Mega Charizard Y.
Meganium's access to Reflect & Light Screen make this all the better, as it can set up a screen or two and switch out to regain a good chunk of health, allowing it to switch back in later on to repeat the process. Leech Seed is also very good, of course, both for Meganium and those that switch in during the recovery switch-out phase, and it can always use Synthesis if the situation calls for it. It could be used as a support in Doubles & Triples very efficiently, as well, due to the fact that it can learn Heal Pulse, not to mention Aromatherapy (which is equally usable in Singles & Rotation). The only real downside is the Grass monotype status. I considered adding a secondary Fairy type, but since Meganium has no Fairy moves, it'd be redundant. Regardless of the slight drawback, if you were to play your cards right, you could essentially assure that Mega Meganium would just refuse to die. That's an astronomical leap over its currently terrible metagame presence -- it's even worse off than Delphox, as the latter at least has a respectable typing and good stats.
Mega Feraligatr
Type: Water/Dragon
Ability: Strong Jaw
HP: 85
Attack: 135
Defense: 115
Sp. Atk: 94
Sp. Def: 93
Speed: 98
This setup is aimed at making Feraligatr a huge offensive threat -- one capable of sweeping a team if given the chance. Its Attack has been raised by 30 points, its Speed by 20, Defense & Special Attack by 15, and Special Defense by 10. This is a much more balanced-out stat raise than usual with Mega Evos, but it works with Feraligatr. First off, he gains a secondary Dragon typing, which gives him STAB for his Dragon-type moves. Second, his Ability, Strong Jaw, effectively gives him STAB for his bite-based moves. This raises his coverage potential to a much higher level than before, as he can now get a 50% boost for all four of his main attacks worth using: Waterfall, Crunch, Dragon Claw, and Outrage. Combine any three of these with a Dragon Dance, and you're looking at a very powerful & relatively fast gator that can take out a variety of foes. Sure, his moveset is still somewhat limited, but it's all he'll ever need. After all, Greninja is pretty much the same way regarding having access to such great coverage with so few moves necessary, and he's a terrifying sweeper WITHOUT a Mega Evo. If Mega Feraligatr can get a Dragon Dance in, he'll be one tough opponent to deal with.
Mega Typhlosion
Type: Fire/Ground
Ability: Flash Fire
HP: 78
Attack: 134
Defense: 78
Sp. Atk: 149
Sp. Def: 85
Speed: 110
This setup is basically designed to make Typhlosion what he would have been had his Hidden Ability (Flash Fire) been released, only on an infinitely higher scale. His Attack has been raised up by 50 points, his Special Attack by 40 points, and his Speed by 10. Naturally, the main goal would be to predict an opponent's Fire-type attack, switch Mega Typhlosion in, and have him gain a 50% boost in his own Fire-type moves while simultaneously taking zero damage, leaving his HP in tact. This would raise the power of his already mighty Eruption to unbelievably high levels of damage. Anything and everything that doesn't resist it would be OHKO'd with his HP being maxed out, no questions asked -- and, hell, a decent amount of Pokémon that DO resist it would be OHKO'd. Fire Blast is always there if his HP has been lowered, of course. The huge Attack raise is to allow him to run mixed sets, as his moveset almost requires it to be effective at coverage, and the secondary Ground typing is to give him STAB for, well, his Ground-type attacks (namely Earthquake). It also nullifies his weakness to Stealth Rock, as well as Rock-type attacks in general, and gives him an outright immunity to Electric attacks. It DOES give him a 4x weakness to Water and gets rid of his Grass & Ice-type resistances, though, so, much like with Mega Sceptile, there's a drawback to the new typing. Still, this Mega Evo is bound to make Typhlosion a sure-fire hit in the metagame.
Metagross
You'd think being a Steel-type pseudo-Legendary would make Metagross a Pokémon that doesn't need a Mega Evolution -- and in the past, that'd be true. But this is now, and Metagross has unfortunately been nerfed, courtesy of Steel losing its resistance to Dark & Ghost. This means he has four weaknesses instead of two due to him being part Psychic, and that's never a good amount of potential threats to deal with for any Pokémon, even a defensive one. Well, fear not, you fusion of four Bellums, for this Mega Evolution would bring you back to your former glory were it to exist!
Mega Metagross
Type: Steel/Psychic
Ability: Filter
HP: 80
Attack: 155
Defense: 150
Sp. Atk: 105
Sp. Def: 150
Speed: 60
This setup gives Metagross a ridiculous boost in Special Defense, skyrocketing it from 90 to 150, which is a whopping 60 point difference. His Defense also sits at 150, and his Attack sits at 155, both having been raised by 20 points. This makes him defensively on par with Aegislash Shield Forme, and places his Attack stat five points above that of Aegislash Blade Forme. In addition, his Special Attack has been raised by 10 points, and his Speed has been
lowered by 10 points. You may be wondering why I lowered his Speed stat. Well, it was a necessary change made to accommodate for the total boost in all the other stats totaling 110, as all must Mega Evolutions receive a net increase in Base Stats by 100. It's a minimal drawback, though, because with his good HP & awesome defenses in tandem with the Ability Filter, which cuts the damage of super effective hits by 25%, Mega Metagross becomes the
definition of a tank, capable of wreaking havoc in the game more than he could ever have even dreamed of while in his vanilla form. This Pokémon's meta is gross.
Gallade
Just like how Swampert & Sceptile deserve Megas by default due to Blaziken getting one, Gallade deserves one because his counterpart, Gardevoir, got one. It's just not fair that one part of the Ralts family is being shown favoritism while the other is getting snubbed.
Mega Gallade
Type: Psychic/Fighting
Ability: Super Luck
HP: 68
Attack: 165
Defense: 75
Sp. Atk: 75
Sp. Def: 125
Speed: 110
This setup is designed to take full advantage of Gallade's potential as a sweeper. His Attack has been raised by 40 points to a staggering 165, and his Speed by 30 points to a solid 110. The rest of his stats (save HP, as that's never altered in Mega Evolutions) have each been upped by 10 to fill in the remaining 30 points. These stats alone make Mega Gallade a threat, but it's his Ability that makes him a true nightmare. Super Luck raises the critical hit ratio of moves by one stage, and boy, if there's ever been a Pokémon to abuse this Ability, it's Gallade. He has an astounding
five high critical hit ratio moves at his disposal -- they being Psycho Cut, Night Slash, Leaf Blade, Stone Edge, and Slash. Gallade to Super Luck is the equivalent of Scizor to Technician. Slash, of course, is useless in the modern metagame (and has been since post-Gen III), but the other four moves are all unquestionably capable of wreaking havoc, especially Stone Edge. His HP & Defense are still somewhat low, though, so he's still a little frail. However, if Blaziken has taught us anything, being a frail Fighting-type is far from being at the top of a worry list.
Arcanine
Arcanine is a Pokémon that has withstood the test of time relatively well. However, its Fire monotype hasn't done it any favors, and its base 95 Speed isn't anywhere near as good as it used to be. Naturally I've set out to fix these issues with this Mega form, and I think you'll like how I've laid it out.
Mega Arcanine
Type: Fire/Dark
Ability: Reckless
HP: 90
Attack: 140
Defense: 90
Sp. Atk: 120
Sp. Def: 90
Speed: 125
This setup is designed to bring Arcanine back to the glory of his Gen I days. His Attack & Speed have been reaised by 30 points each, his Special Attack by 20, and his defenses by 10 each. This patches up his relative slowness (for the modern metagame), and boosts his offenses to a much higher level of power, making him a lot more capable of handling himself. In addition, he's gained a secondary Dark type to give him STAB for Crunch, and the Ability Reckless to power up his two most powerful moves, Flare Blitz & Wild Charge. Arcanine not only becomes a threat at this point, but he becomes pretty terrifying, capable of dominating the metagame once again. If that doesn't earn him his status of being "the Legendary Pokémon", then I don't know what does.
Milotic
Milotic has always been considered to be the counterpart to Gyarados. It's a Water-type that evolves from a useless fish Pokémon (Feebas), and it has relatively high Special Attack. Sadly, time hasn't been kind to the ugly-duckling-turned-swan. Its Water monotype allows for only one layer of STAB, and it's not very fast with a base Speed of 81. 100 base Special Attack isn't all that great, either. It may have pretty good bulk, but that's it. This Mega form aims to make the gorgeous fish skyrocket from being merely decent to that level of "I swear to Arceus, when I evolve, I'm going to kill ALL of you!" that Gyarados has.
Mega Milotic
Type: Water/Fairy
Ability: Pixilate
HP: 95
Attack: 70
Defense: 90
Sp. Atk: 140
Sp. Def: 145
Speed: 100
This setup drastically alters Milotic's capabilities. Alongside its stat boosts (which I'll detail in a bit), it gains a secondary Fairy type and the Ability Pixilate. This gives it one of the best typings in the game, and with its Ability, it can use its Normal-type moves to dish out Fairy-type attacks with a STAB boost AND an extra 30% damage. This gives the move Round, a 60 base power move, a base power of 117, and it gives Hyper Beam a base power of
293. That's insane. The stat boots it's gained are an increase of 40 in Special Attack, 20 in Speed & Special Defense, and 10 Attack & Defense, making it much stronger, bulkier, and faster. A base 100 Speed still isn't incredible, but Mega Milotic's base HP is almost on par with Swampert's, and its Special stats are phenomenal, so it's not much to worry about. This Mega Evo instantly makes Milotic one of the best Water-type Pokémon in the game, and that's really impressive coming off of an otherwise okay one.
Salamence
Last on this list is the pseudo-Legendary Salamence. Yeah, that's right, both pseudos from Gen III are getting a spot. Salamence was once on par with, if not better than Dragonite, but ever since the latter got Multiscale, Salamence became much less useful in comparison. Add in the Dragon-type nerf with the introduction of Fairy, and he simply isn't quite as good as he used to be. He's still good, of course, but he's
well past his Gen III & IV glory days. I refute that. He has an infinitely better design than Dragonite, and his lore is infinitely cooler, as well. He deserves to be back on par with/better than him. He deserves... a Mega Evolution.
Mega Salamence
Type: Dragon/Flying
Ability: Hustle
HP: 95
Attack: 140
Defense: 115
Sp. Atk: 135
Sp. Def: 115
Speed: 110
This setup makes Salamence one of the most absurdly powerful physical threats the game has ever seen. Its defenses have both been raised by 35 points, its Special Attack by 20 points, and its Speed by 10. Now, without so much as a single point increase in the Attack stat, you may be wondering how this makes him "absurdly powerful" physically. He should be the same physical threat he was before, right? Wrong. With the Ability Hustle, at Level 100, his final Attack stat is raised up to a monstrous 624 -- FINAL, not base. That's the third-highest a final Attack stat can possibly be upon a Pokemon entering the field of play without a form of outside aid (Choice Band, Swords Dance, Baton Pass, etc.), under only Mega Medicham (656) & Mega Mawile (678). Of course, Hustle comes at the cost of accuracy being lowered by 20%, but with Hone Claws being part of Salamence's repertoire, this is hardly a problem. His good defenses & HP allow him to set himself up with relative ease, and if he gets one in during a switch-out/switch-in, it's not gonna be pretty for the opponent -- unless it's something like Greninja or a Scarfed Garchomp. But that's not all. If you can manage to get his Attack raised by six stages in a match (most likely after a Baton Pass), it will shoot all the way up to a sickeningly-high
2496.
Some people would probably find this broken, but keep in mind that it's very circumstantial, and it's still only the third-highest potential out of all the Megas. On top of that, Durant can actually reach higher levels than even Mega Mawile -- a Durant with an Attack-boosting Nature, the Ability Hustle, and a Choice Band has its final Attack stat sit at an unbelievable 696, which can be raised up to
2784, making him capable of being the most physically destructive force in the game (unless you count
Swampert's new reign as the Undisputed Champion of Damage Output) -- so his power is ultimately inferior to three other already-existing Pokemon. Still, with that kind of Attack stat, good defenses, and solid Speed, Mega Salamence can
soar above the competition.
And, I guess any legendary out there would be cool to see as a mega.