Looks like Unity is the engine Microsoft picked this go around to support Xbox One development. Maybe XNA will be resurrected at some point, but I doubt it will be anytime soon.

XNA was nice and fun to program with, but I think Unity is generally a better game engine, it's still C#/.NET development, the base version of Unity is pretty open and free now, and you're not locked into "The Microsoft Platform" with it.

So overall I'm pretty satisfied. I could probably even quickly port some of the XNA code over with minimal changes (not the graphics, unfortunately. Assumed a fixed size 2D viewport for all my layout and animation code, which was a mistake).