I think we're all hoping they add atleast a little extra content.
I'm hoping for no less than 2 extra dungeons.
Maybe one could be unlocked by beating the game, and be playable only by young link.
I don't know when they could slip in a bonus dungeon for adult link, or what they could give you, but I have little fear nintendo could figure it out.
I just want bonus content, preferably a lot of it. Maybe change up some of the mini games, like fishing, to make them show off some 3D.