While I do love this game, it does have a number of flaws; however, they can be easily fixed, which is a good thing especially if a remake were to be made.
I guess the main problem for some, or complaint, was in fact "difficulty". Now while I disagree that this is the easiest installment--as I found The Wind Waker and Skyward Sword vastly less challenging--it does have a number of aspects that could be improved. Much like The Wind Waker HD has added, this remake could have "Hero Mode", which would certainly make a lot of enemies and bosses alike more threatening. Since this was definitely one of TP's main drawbacks I think this could be very effective, especially for those experienced players
However, Hero Mode isn't enough in my eyes, I'd like to see some more noticeable changes. I was thinking a combination of Master Quest as well as Hero Mode; this will freshen up some dungeons and puzzles which would be great for people who know this game inside out. So while not too much can be done on the difficulty side, a harder mode - maybe a hybrid between MQ and HM - would be very effective in my eyes.
One major addition in my opinion would be the Hidden Skills. They really enhanced combat in my opinion, I would even say TP was the pinnacle in terms of combat in this series - so why not add on to one of its most successful additions? Well there is one slight problem and that is that they make taking down enemies a lot easier, but with Hero Mode this could balance out somewhat, but I'd still like to some sort of challenge in obtaining such skills. Maybe you have to defeat a boss-type enemy, traverse through a hidden cave etc.
Obviously the graphics will get an upgrade and that will look amazing, so I think that will be covered, but I'd love to see more realistic settings and whatnot. TP is definitely the most realistic, visually, so why not expand on that? A popular choice would be a brighter colour scheme. Now I tend to argue with a lot of views on the colour scheme itself, but it definitely could do with a brighter colour scheme - just as long as they keep that darkish theme that the game is known for. Adding to this would be character models, even though the setting resembled realism to an extent, the character models were still very anime-ish in my eyes. So maybe a slight change to the character models; however, that's about it on the visual front for me, just a slight upgrade, nothing too drastic, as I did love the graphical style for this game.
If this remake does come on this generation then we're sure to see a new and enhanced control scheme. The GamePad will obviously get rid of the latter control scheme (for the Nintendo Wii). This will be a big plus for some, as the lackluster motion control with the Wii Mote and Nunchuck was criticised by a few and a lot do prefer the Gamecube version. This control scheme could take advantage of both, you could have the Gyroscope for precision aiming and other motion uses. The button and stick combination will be the main usage and you could even implement the touch screen to make markings solve puzzles and maybe for the howling stones etc. So it's no doubt we will have a top notch control scheme of this were to be released on the Wii U.
I think this could also be the perfect time to implement some connectivity with Mii Verse. Maybe not taking a huge step in terms of online co-op and multiplayer, btu some sort of connectivity between players online. You could have leaderboards etcetera. - I think this could work hand in hand with a boss rush mode or an enemy hoard mode. Thinking about it, you could have a dungeon rush mode, seeing how long it takes the player to navigate their way through selected dungeons and maybe even the cave of ordeals. Overall, Zelda may not built for online modes and such, but it can certainly take advantage of Mii Verse connectivity. Another add on to do with Mii Verse, and something I've wanted for a while in Nintendo games, would be an achievement type system. I think this could work wonders, especially for a game as large and as expansive as Twilight Princess, just adding miscellaneous challenges for the gamer to complete could add so much to an already big game.
Adding on to what I mentioned easier--about modes and whatnot--this could be a prime time to add in multiple modes. So the HM/MQ mode, which I mentioned earlier, could be unlocked after completion, but we could also have some different modes - this could add to the longevity of the game itself. The most basic, in my opinion, would be a "mirrored" game mode. since Twilight Princess already has two versions that mirror each other, this actually wouldn't be too much trouble for the developers and it will give gamers a chance to experience both versions - as there may be many who never got to experience the other version. On top of this, we could have a "three heart" mode or a "minimalist" game mode. Since these are heavily popular among fans, why not actually make them a part for the game itself? This doesn't just apply to Twilight Princess, but any new instalment.
So these would be my main wants, but I'd also like some very minor changes; such as the game letting you know you've found a rupee, which was actually really annoying after a while. I'd also like some improvements to a few quests, just to make things run slightly smoother. One final minor change would be to allow for own more wallet upgrade and to actually get a wallet upgrade earlier on in the game, as the amount of rupees you find compared to how much you can hold is unbalanced.