Blind, sap, and kidney shot are your friends in those situations. Also with multiple mobs hitting you, combat readiness stacks very quickly.
Combat is actually my favorite spec. I don't mind if it's if slightly behind--as it was in 5.0/1. The set bonus puts it considerably behind assassination now, which means I'll NEED the 4-set to be able to play it. I finally got my t14 4-set LAST WEEK. It took the entire damn tier to get the current 4-set--I do not want to deal with that again. That and I have yet to see a normal mode dagger. And have only had 2 lfr daggers drop--for the whole tier.