Can't agree more here. There is also one small fact that makes me kinda dislike Vol'Jin:
After badmounthing Garrosh for one time too much he gets a dagger in the neck. Fortunately tho, Trolls seem to not need blood flow to power their brains, so he survived. And heres the situation: the Darkspear are left leaderless, and continue to live in Orgrimmar and in close provimity of Orgrimmar, being loyal to Garrosh (unaware he actually tried to kill Vol'Jin).
So, in such a situation, what is the worst thing any leader can do? Well, openly declaring that he survived and that his people are now the enemies of Garrosh seems like a good pick. Yeah, I'm sure they are very gratefull being stuck in the middle of their enemies capital without outside help.
The Horde is really entering the golden age with such a genious leader.