This is the same strategy Blackberry tried, more or less, and I'm skeptical that it'll work out any better for Microsoft.

It's nice enough in the short term, maybe -- Windows Phone users can get some subset of quickly-ported things -- but in the long-term it seems to doom Windows Phone to second-class status; why would you write a real, native Windows Phone app when you can just do a quick half-assed port of your Android/iOS version? And if Windows Phone is just a platform that has a bunch of outdated, bad versions of some Android/iOS apps, there's not a lot of reason to buy it.