What if the coliseum were somewhat team or Klan based, with every Defending player representing a thread and every attacking player attacking the whole thing. You can back out to save yourself for a round but the defender gets healed partially after that.

While this would be fairly dull as hell right now, once we get status ailments going it could lead to some interesting raids as you’d need a diverse party to take down some people especially if you give the defenders a bonus since they attack second.