My main problem with WP is that it's too monochromatic and it translates into the apps. We could have more than black/white with another colour and still have a high contrast. And Start screen backgrounds don't cut it for me. As it stands now, I'd much rather have the possibility to customize the colour of all tiles while having no background (as in the tiles would be touching each other).
As for the apps, I have to agree that most in the store need some serious design overhaul. There are some really beautiful ones, like Oggl, Atmosphere, Wunderlist, Magnify, Poki and Cal. But the vast majority is just poorly designed. It's bad enough that there's very limited functionality and support on some of them. Even worse is if they're ugly. Now, I'm not gonna say that the iOS apps in that "top 10" link in the first page are greatly designed. Well, some of them are, but none is worthy of a top 10. If you want to see good and nicely designed apps for iOS (and OS X for that matter),
this is the place to go.
Yes, there is inconsistency on iOS and specially on Android. But there are apps that make you want to use them just for the joy of looking at them. And WP is lacking in that category and it's one that is more important than you think.