the main..."strength" of the bard are:
- can use him skill while moving
- attack from far
- have infinite tp.

him damage alone are not that good, but it have all the good point of the caster and the melee.

about the drg tradeoff, they are at close range and have the worst magical defense (most of the attack hitting the drg are magical damage).
i think like sentinel, the skill of the bard must be rethink and he need to get some skill that make him stand a bit.