The new Revenge wich allows you to cleave another target also works without any dmg reduction on faction champions, seeing they have 75% reduced aoedmg taken(or somewhere near there), this is an exploit.
This may work on other mobs that have aoedmg reduced.
Also found that this works on the adds at Deathbringer saurfang in icc10/25, seeing they also have reduced aoe dmg taken.