Meh, I'm really not for co-op play for a Zelda game. I mean I suppose it could work like it did in Four Swords, but I don't know. Playing as another character just seems a bit out of place as well. Your ideas are definetely new and fresh, but I just couldn't see then working for a Zelda game. They aren't bad, just out of place.
Personally, I couldn't care less about new ideas for Zelda games. Just nothing to over-the-top like Link riding an airplane. I suppose new ideas are better, I just have a tough time thinking about them. I'd love to see the Trading system make a return, I could just spend days on that system and still enjoy it.