Most like the Shaman setups (x5 Shaman/x4 shaman + 1 Paly) because they are viable in both PVE and PVE. Can you instance as 5 mages without heals? Very unlikely. You can, however, do it with Shaman (or a well-balanced group). I am sure a x5 mage group would be awesome in PVP/PVE w/ out instancing. But personally, I'd much rather PVP 5 Warlocks