I don't believe that we will controll a different character, and have little doubt that Link will be the main character in the games yet again. I don't see why this would occur so late on, or at all really, and I feel that we'd have already found out about it in some way, unless Nintendo are keeping a 100% secret outside of the Zelda team. All the trailers that we have seen show the player controlling Link, and no one else. We might get something like in Twilight Princess where if you struck a Cucco with your sword enough times you were able to partially take over it, but I don't think it will be much longer than that, to be honest.
I don't think I'd really be able to adapt to Link not being the main character, maybe if we got to play as another character every once in a while, then it might be pretty cool, like in Bowser's Inside Story, in which we get to play as Bowser as well as Mario and Luigi. It could possibly work to, but I think it would be best suited as a DS game. But I don't think Nintendo will ever pull a move off like that, so I can't really see Link not being the main character in the series, ever.