I did this for some fights on my druids. Like the elemental/golem in GunDrak, with his aoe poison, one druid just didn't have the oomph to heal through it ticking on 4 guys. With the 2nd druid specced resto, wild growth x2 just nerfs that fight to stupid-easy. Some fights you cannot do that though as the boss will enrage after a certain amount of time. Like Eck. Or the first boss in DTK's stacking rend DoT thingy.