A similar scenerio would be if you took one of the tanks and cut their health by 60% and let the other tanks keep theirs. (This is the reference of kitty dps vs. caster dps atm as all melee are down.)
that would suck... if i cared about pve as much as i care about pvp. on my part itd be more about my mana pool or resil or even CDs on certain spells that help my survivability.