Shattered Hand were in Spires of Arak for god knows what reason not really doing anything at all, further emphasized by the fact that they were mostly dealt with in Bonus "Quests". The other orc tribes were introduced through occasional pillaging in otherwise harmonious areas, though their influence never seemed to extend beyond whatever quest-hub they were found in. The conflict between Orgrim and Durotan was supposed to be great - Orgrim seemed perfectly fine with the whole conquering-business until he suddenly made a u-turn when asked to kill innocents and was killed off, having gone through no visible development whatsoever. The large majority of dungeons is just there with little to no context or anything that leads into them.
As far as atmosphere is concerned, only Spires of Arak felt great, as the area largely focused on the Arakkoa, giving them enough time to properly explain what's up with them. Almost everything else was just there with little to no explanation and only minor development.
Nagrand was a huge disappointment and I was just wishing for it to end because the fight between Garrosh and Thrall was supposed to be great. However, the final attack on Grommashar was hardly exciting; not sure if the scenario-style simply doesn't work for me, but I had a hard time feeling like anything was at risk. I was rather questioning Garrosh's approach, as all he did was sit on his throne, throwing one completely harmless obstacle at me after another. I also tried to get included in the battle, saving my soldiers who were close to dying, but they were scripted to die the instant I use an ability on their opponent, so that didn't work out too well. I tried stunning their opponent and killing them, but the saved soldier simply despawned afterwards.
So there I was, storming Grommashar with a bunch of nameless goons I had no chance of saving. After living through the whole ordeal, I was treated to a great fight and yet another personality-change for Garrosh, which would be the fourth time for him. Fortunately, they finally managed to kill him off after having him go through a life of being a guinea pig for personality tests.
With that, it was over, Nagrand having been the final area for now. During my journey there, I also killed the Fury of Earth by myself and then managed to duo a Void Lord together with Drek'thar. I understand that questing is supposed to be a solo-experience nowadays, but that hurts the atmosphere more than anything - it's hard to feel excited about anything if there's no way I'll die.
I really hope Tanaan Djungle will have a somewhat final feel to it, but there hasn't been anything like that since Icecrown, which actually managed to be atmospheric, as did Northrend.
Though, to be fair, the Goblins at the digsite in Nagrand were awesome. "Let's do archaeology!" "Use your archaeology blasters!"