How about giving bards something like a new AC song or a new dmg increase song instead of this? The reason is because I don't think ive ever seen even an enc cc on this server, nevermind a bard >< I know if I were playing a bard i'd much rather have a boost to one of my other songs that are used often.
Here's the current best AC song for bards: http://clone.thehiddenforest.org/spell.php?id=1763 it scales up to about 100 AC with max instrument mods. Not bad, but not as big as it was on live either. For PoAir level I think something along the lines of 2-300 is more suitable. Bards used to be begged to be in MT groups on live just for there AC boosting capabilities, this was back when 2.5k-3k AC was high though!
If you'd prefer a new +dmg increase song that's fine too, the current best is: http://clone.thehiddenforest.org/spell.php?id=5388 If you do that instead, you could also customize the overhaste to something that'd actually be used ><. As we talked about a long time ago, people are already at the minimum delay and beyond with the current haste cap.