Hi all,
I tried to find similar post, but without success, so will suggest, that idea was not yet mentioned.
Arena by itself is a good encounter. The only problem - it is starting too fast. It is causing issues on low life build, like lich. On some arenas I have like 2 secs after its loaded to react for any monster. Because of that death is almost instant, when mobs are spawned nearby.
So advice is next:
Add countdown or some sort of damage prevention buff for a couple of seconds or until player do something. This should help a bit for low life build to react after arena zone is loaded.