I don't think Mac is being abandoned at all, for xLights... just xSchedule. In fact, Dan Kulp has invested the time/effort to get xLights into the App Store. Apparently, having it in the App Store also allows for deeper crash reports and debugging info. If anything, I wonder if Mac will be the best platform for xLights for that reason.
I personally use FPP for the scheduling side of things, and like that it is dedicated and separate from my sequencing machine.