I wouldn't say Samsung, Moto, and HTC are "miles ahead of Nokia". They're running essentially stock Android with crappy tack-ons that nobody cares for (when's the last time any OEM's take on Android has received praise instead of complaint?), being glacially slow with updates...

With stock Android as a starting point and, well, a clue, Nokia can easily overtake Samsung, Moto, and HTC. Just by keeping good time with Google's own updates, and developing a customized Android UI that doesn't suck, Nokia can pull ahead.

That being said, I think the WP7 choice isn't a bad one. At MS Nokia would be customer #1. At Google Nokia would be just another OEM.