Nokia should go all in on Windows Phone.
But, you've given no reason why you think they should do so, and the market has, so far, said that Windows Phone is unexciting. I'm gonna believe the market over a random guy on the Internet, unless you've got a pretty good reason to think two losers will combine to make a winner.
My needs are simple. I need useful stuff on my home screen. No other OS does it better.
I've heard this said of WP several times, and I still don't know what it means exactly, or why I should want "useful stuff on my homescreen". My phone is in my pocket until I want it to do something (make a call, search the web, find some place in maps). The home screen has nearly zero value to me...it's mostly just where I go to find which app I want to use, and I don't want it cluttered. I use a second page for weather and twitter apps, but I can't think of anything else I'd want on the home page. I already get notifications for texts and voicemails, and I don't think I would want them to be more intrusive.
I purchased a new WP7 device recently - my first smartphone (HTC HD7S). The useful stuff on the home-screen is actually v nice (1 tile for weather, one more tile for people etc).
Also, here's an article on how 3rd party apps can leverage the tiles for notifications. It is obv. not WebOS-like or anything but it is a neat approach to delivering notifications : http://chriskoenig.net/2010/08/16/customizing-wp7-push-notif...
Right now, the third-party app catalog is not exploiting the tile feature so well. I expect this to change soon.