On ToP 2, I believe the Arena Administrator got an option with a full heal that was quite expensive (10k?), honestly although Bar PvP died around that time, it was a cool feature. It allowed matches to be more dynamic, as you didn't have to wait for that one guy who doesn't want to use cakes to heal up.
One thing this would kill is the nostalgic feeling of dying in a PvP/MvM match and then having to sit down and wait till you're full for another round.