Actually, maybe do us one better and make it available for all Windows devices (phone & tablet), please?
Great idea.
Now if only they would do it...
Or, get a android emulator and play on PC
Bluestacks is descent...
http://www.bluestacks.com/terms-and-privacy.html
I would prefer a windows app ..
I have Bluestacks on my PC, but I would like to be able to play on my phone
Bluestacks works great on PC, but the advantage of Windows 8 - Windows 10 is that the same apps that run on your Windows Phone can also run on your PC without any real additional programming on the part of the app developer. Halo: Spartan Assault and Halo: Spartan Strike are a good examples of their buy once play anywhere model.
Microsoft's also alluded to the idea that when Windows Phone 10 launches app developers will be able to port directly with little conversion from iOS or Android. Given the Tech Preview is a free download and that the SDKs are available, I'm surprised they aren't hopping on this already.
Then there's also the fact that Xbox One is running Windows 10 alongside the Xbox OS and that they could release Fallout Shelter on three platforms without much difficulty...
But at that point we're getting into wishful thinking.
EDIT: Here's the link to Windows Bridge for Android in case one of Bethesda's developers is feeling adventerous. https://dev.windows.com/en-us/bridges/android