I think the "atrocity" was already committed, forcing his own people to get possessed by the Sha, which destroyed them all outright. But I guess that's not enough either.At worst I'd say Garrosh would try and use the Sha again but Cho Lorewalker tries to persuade him but Garrosh kills him in outright cold blood. That could be one reason for Pandaria to fear Garrosh's regime. It may not necessarily piss US off but it will annoy the Pandaren enough to stand up to Garrosh and thus maybe smack some sense in the Horde. I'm sure the plan will be much more grand but it's an idea I'd like to see if it was possible.