No way, I'm pretty sure if they hadn't have just said "lol Org is ours now" any number of races could have posed a serious threat.
We didn't exactly have a huge backing during SoO, there were a few appearances, but no major force stomping their way through half the place with us. Just that one little section before Spoils etc. I'd even say that Bolvar LK still has stronger forces and could decimate them if it came to it. Not to mention the fact that the Klaxxi were the second to last boss in the raid not the Kor'kron and sure it was their paragons, but imagine the whole might of the mantid army raining down on Orgimmar, I don't see there being many survivors, only reason the Panda's held them off so long was that big ass wall.