Almost all of the 122 (and counting) things that Windows Phone 7 cannot do in comparison to Symbian, Meego, and Maemo are likewise common, routine things that iOS5 and ICS can do.
Are there no things that WP7 can do that those other systems can't? Off the top of my head, I'd place a substantial bet that the breadth and depth of games on WP7 is much higher than Symbian, Meego, or Maemo, which is something that average consumers care about.
Also, while some things on that list are real issues, some are subjective at best (ie "Very limited customization option" and "Tiles are fixed size and for many functions is a waste of space."). Many more of them will be fixed with WP7.8 or WP8.
However, this thread started as the future of Nokia. The merits of Maemo and Meego are irrelevant because Nokia can't go back to them. They could build a new in-house OS, but it might be years before it's ready. Other than that, the only options I see are WP8 or Android. If you don't think they should build WP8 devices, do you see an option other than Android?