This is what I think (from quad shaman perspective):

The OS bang bang kill will be even harder to achieve on hard targets...
...BUT since you survive longer I believe you'll also have more time for purging targets and make target softer.

Burst on one or more of our toons was also a problem to our healers so we also benefit from it.

I think that we'll see more teams of non boxers with 4 dpsers.
Main targeting the healers is now more interesting than ever.

I'll have ready for this season 4 warlocks and dk+4 rets as well as my shaman team.
We'll see