Smash Bros and Kart 8 bundles with added pro controllers are the better bets, honestly. What kept the GameCube afloat, and what differentiates Nintendo from the competition still, is a focus on local multiplayer experiences that you simply can't get anywhere else.
I've noticed a fair bit of doubt as to whether either title will do anything to make a difference, but both are uniquely positioned in the hearts and minds of gamers, and more importantly, while both have iterations available on 3DS, here we see a more compelling reason to buy a Wii U for these games because local multiplayer is, in the West anyway, far more of a console-oriented experience.
So those two games are where they should go all out.
Monster Hunter: pissing me off since 2010.