You could swap jobs at will during the fight?
Since this is a PvE centered game with tons of Lore things tying up PvP creating a terrible imbalance in relation of a class against another to a point in which a perfect balance would be nearly impossible to achieve...
how do you think a 1vs1 duel like this would be from your PvP veteran point of view?
Of course with limitations like No Cross-class skills, possitive buffs wiping on swap, no reset of used cooldowns, only 3 jobs...
Oh well, you get the gist of it...