Has 2v2, 3v3 and 5v5
Instead of players killing each other they compete to kill waves of monsters
There are multiple waves of mobs and Mobs will disappear after a certain time limit
For example if you get 10 mobs but you only kill 7 and they disappear then the enemy group could be in the lead because they killed 9 mobs.
Every time a group kills a mob they get points for it.
Mini bosses will appear at certain times and reward extra points if killed.
Which ever team kills the most mobs before the match ends will win.
If a team manages to collect the maximum amount of points before the enemy team, they will win.
Guilds can maybe vs each other in 10vs10 too compete in a new type of guild tournament.
Rewards can be new armour which would be very effective in dungeon and less effective in PvP or New accessories that current arena doesn't offer.
Just a suggestion.