Nintendo blocks 3rd party games...

[curl-6]

There's already a hardware feature that block third party games, it's called the Nintendo logo.*

To answer your question, yes I would. The Wii had enough first party gems to justify the cost of a console, and the Wii U will probably achieve the same. That said though, it would have been a real shame not to have Monster Hunter Tri and Goldeneye 007.

*Just so I don't get modded, I am joking.