How does one cope with it? Granted the point where it annoyed me there was 3 archer bosses in close proximity all mana burn, but i could see it becoming a bigger problem as i advanced into hell. Have to get too close for warcry, often have no mana for it by the time i'm there. Boss packs immune to howl. I suppose i could taunt them away one at a time, but at the frequency mana burn packs appear i wouldn't want that to be too often.
If it matters:
My build is a bit weird. I haven't played many barbs, so i maxed sword mastery and took 1 in each combat skill so i could try them all.
1 in each warcries skill, maxed BO, almost maxed shout. Using an eth oath balrog blade paired with a lightsaber or using the balrog as a 2her for sections where i'm doing a lot of berserk. Duress armor, gores, mara's, ravenfrost, and various random sets/uniques/rares for other slots.
That said, the kill rate isn't that bad, just found this mana burn situation frustrating ;) And if it was likely to be common was leaning towards not trying to setup a barb next season.