The implementation of the Master Sword in this game makes no sense, not to me. It's too easy to get 13 hearts and get it, but then it's relatively weak unless used only to "seal away the darkness". But when that happens, it IS very useful ... 60 damage per hit, and about 200 durability. Recharge time is only 10 real minutes, and from what I understand, the recharge times for everything are about 2x as fast when in Hyrule Castle ... so in there, it's almost a permanent weapon.
But back to my point ... The fact that there IS durability in this game is what causes the first issue/hurdle to deal with. How can you give a permanent weapon that's supposed to be "the bad-ass" to someone with only 13 hearts, early in the game? Your only real reason to use a different weapon in this game would be (examples now): Blizzard Rod for crowd control ... a spear for when you need a little extra reach ... or a two-hander for if/when you want to do the "spin to win" move. Other than that, this game would just become a pure slash-n-hack combat system with an unbreakable mid-range power sword. That can't happen, not the way this game is made.
So, my idea would have been to be able to get the sword early on ... maybe at 10 hearts ... but like in past games, you have to slowly power it up during your progression (but that too presents another potential problem, since this game wants to do as little to direct you as possible). Trial of the Sword (via DLC) is a nice adder in that it allows you to power up the sword to 60/200 permanently ... but that should have been A) in the base game design ... and
should have been something like, you can't even do the beginning trials until you've done X ... then only AFTER that ... you have to go do Y before you can do the middle trials ... and then you can finally get to the Final Trials after completing task Z. Now, even more importantly, there would HAVE to be some required linear progression system in the game that kept you from getting through that process too quickly ... so that you don't have the fully powered master sword until "late in the game" so that you're prevented from having an over-powered, almost permanent weapon too early on.
Not to get off topic ... but as great as this game is, the degree of "open world" that this game allows is too much for a Zelda game. I don't want strict linear, hand-holding like some of the past games, no way. I do want, however, a required linear progression where it's not a straight line. Sets of tasks to complete, but done in whatever order you want ... but you have to do "all that stuff first" before you can start getting into other areas and new tasks ... and you slowly get powered up along the way. This way, you can allow the freedom to explore areas just like now ... but you may be limited to say, 1/5 of the map until you've cleared that area ... then you get to the next area, so on and so forth.
Anyway, back to the point... I think that given how the weapons/durability/combat/leveling-up in this game works, the MS is fine ... I just think that overall, it's a bit weird. If the MS is going to be in the game, it needs to be a bad-ass, at least eventually. That happened in this game, but only via DLC. Think about it ... a 60/200 weapon with a 10min recharge is VERY powerful, especially knowing you can take it from it's "like new" state into any battle and clear out everything in the area.