Is this a good arena/pvp combo(arcane fire mage)?

Virtually every comp is viable, I think Arcane mage and Fire mage would be great together actually. I'm not too sure if both mages would share diminishing returns on the sheep but it's definitely a burst comp. It would be a lot better with Frost Mage/Arcane Mage due to the amount of CC. IF your going up against a priest you need a way to constantly lock him/her down because that pain suppression will consume a lot of your burst.