Any aoe causes massive stutter/lag which is worse the bigger the mob; more pronounced in dungeons than overland, about the same for pvp. This only started after the the last maintenance (or maybe the one before); after greymoor anyway.
Still getting lag and desynchs: hold block forever and still get sent flying. Skills unresponsive, dk chains in particular (the fighters guild one is ok).
Look at all these posts saying things improved with statements like. "I crash less often" and "The lag isn't rendering the game unplayable" or "I get my infinite loading screen a little later now"
Until performance is excellent, I will give ZoS zero kudos. This is like paying for a car that can't go faster than 10km/h then they boost its speed to 20km/h (for some) and they're like. "Oh thanks you, might ZoS."
The first day was a mess, and I couldn't fire skills. I could even slowly kill an unresponsive world boss.
But once everything settled in, I could play as smoothly as ever. Never encountered any bugs or performance problems. (except the misaligned mythic chests, of course)
Its still far away from perfect or without problems. Even if it feels better in most cases, there is still no need to stop workin on it. Please keep working on it. Players will surely appreciate it!