I'm really enjoying it so far (up to the level 75 quests in Rak'tika currently), but there is one small part that sucks...
Ran'jit. Guy has no personality, no reason to be crazy strong, unbeatable, and able to quickly head us off everywhere. He's obviously just a cheap plot device to make us feel like there's even more urgency, and it's not needed. And he's there constantly.
Everything else has been really good though. And much better at conveying the emotions they want to get across compared to previous expansions, other than they did with Yotsuyu and Gosetsu.