Reminds me of when Bolvar died in Wrath. He was a pretty big deal to alliance throughout vanilla and burning crusade as he was basically the human leader. Then he died abruptly and for no good reason.
At least nazgrim's death makes sense. He is an honorable warrior. You don't get to be a general in the horde by picking and choosing when you want to follow orders, you just keep your oath and serve loyally. The best you can hope for is when you kill him he says something like he knew the warchief was terrible but it was his duty to serve.
I honestly have more respect for those who continue to serve garrosh and end up getting killed because of it than I do the oathbreakers and traitors that turned against him, despite the fact he is a giant pile of crap and a terrible leader.