The problem was not conflag hitting too hard.
The problem was Conflag/Chaos Bolt/Immolate hitting hard in conjunction with another player to instantly kill someone in 3 seconds flat with no way to predict what was coming.
Take a mage and a destro warlock.
Warlock does above - Immolate, Chaos, Conflag, and perhaps throws in a Shadowburn or something at the end.
Mage does Arcane Blast, Arcane Blast, Arcane Barrage, Missiles proc.
That, on a zero resilience target, with zero crits, is 30k damage in 3 seconds. Minus 12% for 26.8k damage, but then add 20% crit rate at 166% (26.8 + 26.8 x .2 x 1.66) = 35.7k
Heal through that, I dare you.