Ah, to be a game developer. You work hard to get a game out by its release date, then the game is pushed back for purely corporate reasons. Gamers are reasonably upset, so now you need to appease them with new content. So, more work for developers to fix the PR problem that the suits created.
While this situation sucks for game developers, Wii U owners will have access to an exclusive challenge mode. This seems to be more than a mere demo, as Ubisoft is promising regularly updated challenges from April onwards. These challenges will support up to five players, and will also have support for leaderboards. It’s unclear if the challenge mode will consist of original content or content made for the TV.
As a note to Wii U fans who are upset, keep in mind that any sort of boycott will just show that the Wii U is not a viable console. Play the challenge mode. If you like the game, buy it. If you don’t like the game, don’t buy it. Don’t cut off your nose to spite your face.