To be honest, I'd couldn't have seen even half of the stuff that they shipped every being there when Visual Studio 2013 came out. An Android emulator? Okay. Upcoming Objective-C support? Hum.
It's a big bet that there is enough demand for better cross-platform code sharing for people to start using the Xamarin environment, and it's even a bigger bet that mobile developers will want to bring iOS and Android applications onto Windows.
There is some method to the madness. The Windows Runtime (the engine underneath Universal Apps) and the Core CLR have some compelling technologies that may have appeal outside the Windows ecosystem.
But, the first form was oriented only towards Modern (metro) applications, and we all know how that turned out. The Universal Apps is doubling down on the underlying runtime and support and seeing if they can get better adoption. Hard to say, but it'll be interesting to see how it turns out.
The other interesting front is Android; there's a bunch of libraries that provide alternatives to core Google APIs. I'm fine with that; alternatives are always good. And the Android subsystem in Windows 10, that's interesting.
Anyway, it may bring some hard-core Visual Studio shops into the mobile space, because you can still say "it's all VS". Lastly, it was a price drop. Ultimate doesn't exist anymore, and it's replacement is half the price. Even Premium was more expensive. I half expect more price drops and incentives to drive more people into the ecosystem.