You can dps while dodging aoe
That, i think, is a fallacy. At least for medium-high ping players. I used to DPS while dodging plumes and was hit often. Strange SE network architecture won't recalc player position in a middle of ability, so it was like "use Bloodletter (any ability with a long animation) -> wild WoTL appears at the same time -> run away while shooting -> hit by WoTL".
So, while bards can DPS and move and the same time, in some crucial moments they need to stop shooting and just run.
OTOH, bard "rotation" won't be hindered much from a loss of 1 second, while blms can get really screwed with mistimed casts and mana ticks.