Demo Locks - Fine without it.
Hunters - Fine without it.
Resto Druids - Fine without it.
Balanced Druids - May need some compensation.
Elemental Shaman - Do need some compensation.
There is no need for any form of constructive response to this type of question, but just for you people that think there is, here is a little..
In blade's edge arena the time it takes for most melee to get back upstairs and on a target while snared, is not much less then the cooldown on knock-backs, now let's include the VERY high possibility of a second player with a knock back being in the team... see where i'm going here?