First up is Bayonetta 2, the upcoming sequel to what I consider to be the finest 3D Hack-n-Slash ever made. The first game had a near perfect balance between style, in-depth mechanics, pick-and-play ability, difficulty, and fun. It's story was batshit insane but its title character was surprisingly likable and well-developed (not like that) and its mythology was memorable and unique.
The gameplay trailer has been released and it looks fantastic, with the same over-the-top and epic gameplay and sequences as the original. I'm unsure how well it will control on the Wii-U but I'm hoping there's a demo so we can hear more from those actually at E3 later on.
It also looked like it had multiplayer, which has been confirmed by Nintendo. I'm guessing it's a co-op system with one player as Bayonetta and another as Jeanne. But that's just what I gathered and I could be wrong.
While Super Smash Bros. is great, this is currently the game that will most likely drive me to purchase a Wii-U. I can't wait.