I just wanted to throw out there that the Android OS has been around for longer- September 2008, to be specific. Windows Phone 7 was "released" in September 2010 (according to Google).
That's a two year head start for the Android OS.
However, take into consideration that the major versions of Android are 1.6, 2.1, 2.2, 2.3, (3.0, but that was only for tablets, oops), 4.0, 4.1, 4.2, 4.3, 4.4, and now 5.0.
That's 11 or so iterations and 11 or so chances at major improvement/changes (although a lot of those revisions were VERY minor).
Meanwhile, WP has 7.0, 7.5, 8.0, and 8.1 (of course, that doesn't account for all the things in between, but those are the major revisions).
That's, obviously, four. HOWEVER, when you take into consideration what 7.0 looked like in contrast to 8.1, you'd see huge changes and huge improvements.
What I'm trying to get at here is that while Android may have more versions and more features under its belt, it has been around for slightly longer.
However, the WP OS has also faced major improvements since 2010. Just because it may not be "up to par" with Android currently (which is HIGHLY debatable anyhow) doesn't mean that it won't ever be. I feel like WP has been doing marvelously with adding new and useful features and I feel like Microsoft will be able to catch up quite nicely.
This is coming from someone who switches between a Nokia Lumia 520 and an HTC One m7, so I'm probably not as biased as some....