I feel like the only person who wouldn't care if it was something new but with old characters like Luigi's Mansion or Kirby's Epic Yarn. I'd only be disappointed if it was something like Wii Music. I'd prefer it not to be tied into the Mario series though.
My thoughts exactly, except with the added bonus category scenario of it being a new game with new gameplay and new characters. After Pikmin I can't help but wonder what else Miyamoto can conjure up from his "based-on-life-experiences" imagination.
After gardening, playing music, watching King Kong (= a contested one), plumbing / visiting New York (?), and exploring the woods and caves of Japan as a child, I can't help but be curious what is inspiring him these last few years. Maybe his kids (= a generation based rogue-like like Rogue Galaxy), learning English (= Wii language University), or even being criticised being the press (= a tower defense type of game)?
Fingers crossed that whatever he is making, it will be something cool, colorful and creative at least.