Originally Posted by
Shadow-cleave
Even so, he still spent years getting the Sin'dorei (not even the race, just the small group he led, which eventually led to Horde being in Dalaran) back into it.
How is he not in control? You try being the leader of a faction/nation of a few hundred people, and weasel out a few traitors (so far, we know of 2. That's it). Up until know, we didn't know Garrosh had spies, and how would Aethas know if they hadn't revealed themselves?
As for the "figuring out thing," Jaina asked him to keep and eye out and he did. He can't find every traitor, it's statistically impossible (much like how America's FBI cannot find every single sleeper agent-terrorist in America, it's simply impossible).
The fact remains that Jaina ousted an entire sub-faction because of a few bad apples (and condemned and slandered the names of people who were supposedly "close friends," even those who advocated for her to get the position she has now *cough*Aethas*cough*).