Advantage of beeing range, compared to the dd's that have the Damage Limit Break. Silence, not sharing the DR of the Stuns beeing the best alternative to interupt. And yeah, Songs are awesome... oh you get that rain of arrows thingy that reduces the damage dealt by 10% or something.
Your class is soooo loaded with support and gives alot of ranged dps, if there is one class nothing needs changed, than its bard.

Also, you just did list a few support spells of other classes, everyone got a bit of support but not as much as bard. At least now, you have to bring a melee on a tight dps encounter, not that they are bad but so far everyone is rolling with 39230532 bards in every raid.