I'd like to have some Nintendo game with bigger 3D worlds. Zelda U is supposedly gonna do this.
I think the problem is that Nintendo doesn't want to take the risk on investing too much money into a new IP that might fail miserably. Nor do they want to pick one of their precious IPs and let them fail.
They're playing the safe game in improving previous iterations of well selling series like New Super Mario Bros., Donkey Kong Country, Mario Kart oder Super Smash Bros.
Imagine the rage of fans if they'd change something major in one of those series and fans won't like it..
Yeah, if Nintendo had the rights for Banjo-Kazooie, they could make some big adventure..