I've got a Wii U, and one of the most fun games for playing in a group is an EA title: FIFA 13. Up to five players, cooperative or competitive, all the leagues and players, recognisable faces. What's not to like? Seriously it's great, and the retailer threw it in as a freebie with the console, along with the pack-in Mario/Luigi platformers.
I've got Mario Kart 8 already. It's a lot simpler and more approachable than some of the previous titles (e.g. Mario Kart DS had a far steeper learning curve) - it feels more like the arcade Mario Kart games than previous console titles. It also defaults to more traditional controls than the Wii incarnation. It's very approachable for casual gamers. My wife and my mum absolutely love it.
Will it be enough to sell consoles? It'll probably sell a few, but on its own it won't make or break the platform - Nintendo needs to follow it up. They need a great Super Smash Bros, a Metroid, a Zelda, and maybe an F-Zero or Star Fox. It's either going to be a great time to have a Wii U as the hit parade arrives, or a disappointing time as ti fails to materialise.