Of course. Not only that but they are trained to deal with the ocasional sha, not the Sha Primes who are supposed to be imprisioned.
They are trained to defend agains the mantid 1000 years cicle, but they weren't expecting it to happen 100 years earlier... during a super major sha outbreak... with the second most powerfull sha impowering the mantid.
And ofcourse they were trained to take care of the rarely seen mogus who came out of hiding now and then while the mogu tribes were mostly busy fighting themselves, not a full fledge mogu empire, with all the tribes united, plus what I think is the full force or at least great part of the Zandalari backing them up and on top of that the god like Thunder King leading them. During the invasion of the sha powered mantid. While dealing with the Sha Primes.
So yeah, it's not that they are weak.