Playing as Bard, how necessary are additional skills?

[Tharian]

The burst you get from BFB, along with the TP sustainability from Invigorate, is really nice! Do a few levels a day, and it's not too painful.

While the DPS boost from Blood for Blood is indeed really nice, the problem is that it gives you just a 10% boost to damage on Bard, while at the same time increasing the damage you yourself take (incoming damage) by 25%. This trade off is problematic in fights such as Titan (Hard) and (Extreme) where you are constantly bombarded with AoE's, many of which are unavoidable. So while it is useful to have an increase in damage, it is not essential.