Fire TB with BotS isn't terrible, it's just kind of mana overkill IMO.
I think fire TB (blood) is good for 2v2, but in 3v3, Rain of Ice + Fireball does more damage than Circle of Flame + Fireball, and chances are, someone else will be tanking. It seems that in 2v2 you need to be able to live a lot longer and take some hits.