Agree with most of that, though I do say the Android/WP7 competition is more dependent on what the end-user wants to do with their phone. Droid is better for people who want control and bleeding edge technologies/applications, however I do feel for 99% of "Joe Bloggs" Win7 is a far superior user-experience.
Right now, WP7 7 imho, is the best OS out there; it's not perfect, and there is some area's where other ecosystems are stronger, but overall, the competition have some serious catching up to do.
I agree with you too, that Mango is simply wonderful, it was the coming-of-age for WP7, and as a long-term WinMo user, it addressed most of the criticisms that I, and the WinMo community in general, had thrown at it. Tango will further improve the user-experience and further answer any outstanding criticisms such as the lack of NFC etc...
If they get this phone into shops for sub-£100 (even £99 lol) then I think the widespread prediction within the technology industry that 2012 will be the year of Windows Phone, should be well on its way to becoming true; can you imagine the sales boom, of a Nokia handset running the fashionable/buzzword Windows Phone for less than £100 in the fall of 2012? As you say, all Microsoft and the OEM's need to do, is keep the pressure on marketing the phones, engaging with the consumer to create more awareness of the system, once most Andorid/BB users pick it up, they will probably fall in love with it's out and out refinement, simplicity and speed, not to mention the impressive and sleek GUI, in comparison to the clunky and outdated interfaces they have been used to using previously.