Unfortunately its a vicious circle, if you don't buy it, then Ubisoft will on the whole stop making big games for the Wii-u, which in turn will mean less people will buy one. I think Ubi is one of the few companies still bothering to make games for the wii-u.
Though I do think it maybe a little late for this now, Nintendo should have made a more powerful machine and support 3rd party with cash. Now the wii-u will be lucky to get support while the PS3/X360 do (2 years) if they are very lucky.