Exclusives sell systems, if i can speak from my own experience. I got a GameCube just for Skies of Arcadia. I got a 360 only for the exclusive JRPGs from mistwalker. I got a psp with the promise of a portable Final Fantasy. I also got a Wii for Xenoblade and The Last Story.
Would i get a GameCube, a PSP, a 360 and a Wii if it weren't for these games ? Absolutely not.
So i guess a multitude of good games could force me to get a Wii U, even though i find it a very bad system.(underpowered, hate the expensive tablet controller)