Yeah yoshis island was a good snes game so that will be good, the link to the past game looks nearly the same except the 2d wall gimmick in this one, it's a shame that no effort has gone into the wii u yet
It's not a gimmick, it's a feature in the game to help solve puzzles. That's like saying the hookshot is a gimmick or the gravity boots are.
The Wii U has tons of games coming out if you haven't looked it up yet, and there's actaully already a lot of good games out for it and games announced/coming out soon:
MH3, The Wonderful 101, Pikmin 3, Zelda WW HD, Bayonetta 2, Lego City Undercover, Game & Wario, Scribblenauts Unlimited, Yarn Yoshi, Zombie U, Super Smash Bros, Mario Kart, just to name a few off the top of my head. Plus we already know the next big 3D Zelda is in the making, the next Metroid is in the making, Retro is making an unannounced exclusive for the console, etc.
You can also bet the reason they had this 3DS conference so soon before E3 is because at E3 they will be able to focus a lot more on the Wii U stuff.