Two healers can out-sustain your burst - focus fire one healer with Mana Burn/interrupts rather than splitting damage.
DoTs and Fear wear you down slowly - burst early before Corruption/Curse of Agony stack past a recoverable point.
You're fighting a very similar kit - win the first CC exchange, since whoever loses their DPS to a stun chain first usually loses the round.
Symmetric comp - the side that lands its Warrior stun and Mage root in the same window usually gets the cleaner burst.