We’ll have to wait for real benchmarks, but integrated GPU performance on these things is estimated to be on par with that of a GTX 1060 while sipping a fraction of the power. That’s not exactly powerhouse territory but it’s a good deal better than Intel integrated and should handle WoW on medium settings pretty well. On the CPU front, some benchmarks were leaked last week and if they’re true they’re as good or better than the 16" MBP in single-threaded, so that shouldn’t be too lacking either.
The Shadowlands beta contains references to an ARM build so hopefully Blizz already has a working port internally that they’ll make available soon.