I had WoW running great on Antergos except during heavy raid/battleground environments with lots of players and combat. I was The runner that was preinstalled with WoW at the time (2 weeks ago? ish?) was esync-staging-pba-3.16. I was only seeing a frame every 1 or 2 seconds, sometimes worse.
I went to configure the wine runners and enabled/switched to esync-staging-pba-3.18. This solved the issue with framerate stuttering during heavy combat scenarios.