To get back to the main point of the thread, BM is an amazing support soul for several things:
1) Bonds: no-brainer group buffs that stack with bard buffs
2) +10% armor for party. This is very nice for the tank
2a) -x% damage for the target. Based on # of bleeds. Anyone know if this works on bosses? Seems OP because a BM can stack 4-5 bleeds up, which would result in -20-25% damage!
3) +10% damage for whole party
3a) +5% damage taken on a single target
A single warrior can only have #2 or #3 up at one time. But by themselves, they are so powerful I'd think that any 10 or 20 man would benefit from 2 BMs in the party.