This is going to be a great partnership. The world's leading phone manufacturer with an awesome OS. It will get better and better. Just look at iOS. When it was released it was laughable and now it is rockin. What is the point of being so disappointed? Just give it some time and we will definitely see success.
I think Nokia has the license to customize WP7 now, which is a good thing. Actually, they claim they'll be working in partnership with MS to that purpose. So, I'm already assuming that the WP7 OS we'll find on Nokia phones will be to some degree different (albait compatible, I really hope) from the one on other hardware producers.
I also think it will be quite likely we'll see other features I can't really understand why are currently missing in WP7, such as thetering and Sync with Outlook.
In other words, I think this degree of exclusivity may be enough to generate that uniqueness that is indeed needed to compete against the iPhone.
Look What Windows Phone Engineering offer ideas on building the next great mobile software developer opportunity:
http://www.forum.nokia.com/nokia-microsoft.xhtml