This goes on both sides of the fence.
Everything from low level mobs to bosses to high level mobs to our own player-based summons suffers from a serious case of snooze alarm.
Monsters take forever to chase down players that are literally shooting them full of arrows. Summons wind up an attack animation to fight against something that hasn’t been there in a good 2-3 seconds. Bosses are free to loose destructive combos on empty spaces that we haven’t even been occupying since their last few attacks.
Speed up the mobs. They should have much more reactive timing than this. It’s embarassing for all of us how slow they are.