Of course it is confirmed Ganon isn't in the game, however it was also confirmed it would lead up to why he would come in Ocarina of Time.
Here's a small theory I have that I hope is kind of right. Like Link and Zelda, Ganon DID have a past life that existed in this game. Maybe its Ghirahim, maybe its some character that overthrows him, maybe its his master. Personally, I don't think he's the main villain. My point is that perhaps Link will defeat a certain character, maybe the final boss, who promises to be reborn into the Gerudo, who's origins I hope are in this game as well, to claim the Triforce.
Think about this, in a way he COULD be in Skyward Sword but at the same time be a different character.
I don't know what everyone else is talking about, but this makes perfect since to me. If there can be a reincarnation of Link and Zelda, why not Gonon(dorf)? Not saying that he has the same name, or same power, but it would make since. And he could promise to claim the triforce in another life, although he may not remember it, since it was his soul or whatever (however that works), he still thirsts for it as he has promised to obtain it in a past life.
And to those who are all like 'But its been confirmed Gonon(dorf) won't be in this game!' and are also all like 'I don't want Gonon(dorf) AGAIN.' Dudes, this isn't a redo, something old that has been done before. This is new! Have we ever seen this happen before?
And guess what, this guy KNOWS Gonon(dorf) won't be in the game, read the top of the post again:
Of course it is confirmed Ganon isn't in the game, however it was also confirmed it would lead up to why he would come in Ocarina of Time.
look at the bold. But this guy then says that he had a past life, that probably won't look, or act, or won't be called Gonon(dorf) (He basicly said that, he said it could be Ghirihim, which is made to be exact opposite of Ganon(dorf) )
(wow, I sound rude in this, sorry! Not trying to be!)