Wonderful 101 and Xenoblade X when it does come out.
That and a ton of VC games/ Wii games.
Yeah there's a ton of good Wii games out there if you can get them for a decent price, the eShop actually does sell a couple of them digitally like Metroid Prime Trilogy. Technically speaking if you really wanted to extend the backwards compatibility, softmodding the Wii mode and playing your GameCube games off an SD card is an pption. The games will have to be those which you own and ripped yourself of course.
watch dogs and assassins creed 3 and 4, they're oldish games now but they they're fun
Oh god not the Wii U port of Watch Dogs. The framerate is extremely low, sometimes lower than 20 when you're driving and around 25 during cutscenes. Better off getting it at any other platform especially when it's more of an average game like Watch Dogs.
Need for speed most wanted for wii u is cool, you get "cheat codes" the other versions don't have.
also: Smash bros U, and New Super Mario Bros U.
MW 2012 didn't really do for me personally, cars feel pretty sluggish compared to the older games and pursuits aren't even as intense and as fun as they used to be. It's okay, but anybody would probably be better off getting the 2005 game imo.