I recently created a pandaren monk and went through the new starting zone. Here are some thoughts and observations. There will be spoilers if you haven't done the zone.
By and large the zone is very good. It's fun, gets across a lot of the themes, and gives a small taste of what Pandaria will be like. The ballon ride is a particular high point.
However, in my mind, there is one major problem with the zone: Aysa Cloudsinger. With Aysa, Blizzard falls into the trap of "telling, not showing". Everyone comments about how amazing Aysa is, but she never actually acts amazing. I think she meditates while you kill stuff, and that's the high point of your interactions.
Whereas Ji Firepaw actually solves problems. Admittedly his solutions are a little crazy, but he is shown doing stuff. As well, Ji is never outright wrong. He's supposed to represent taking action rather than thinking about things. But the downside of taking action rapidly is that sometimes things go wrong. But this is never fully shown.
What's really weird is that Blizzard did not take the obvious route at the very end. Ji uses explosives to get rid of the ship in the turtle's side, which causes the turtle to start bleeding rapidly. This almost gets across the idea of making a bad situation worse, which is the drawback of Ji's philosophy. However, Ji is the one who thinks of using all the healers to staunch the wound. So Ji solves one problem, creates another problem, and then solves that problem too.
I don't really understand why Aysa is not the one who comes up with the idea of using the healers. It's the logical, obvious solution to balancing out the two factions, making them equal.
Also, the way Aysa is written at the end of zone, she is very reminiscent of an unfortunate female archetype: that of the nagging wife. Honestly, for the entire last part of the zone all she does is verbally criticize Ji. She does not come up with any ideas or solutions of her own.
In some ways this male vs female dichotomy is further reinforced by the Horde/Alliance NPCs. The Horde representative is male, like Ji. The Alliance representative is female, like Aysa. So the final choice has a very strong male vs female vibe to it. And in my view, the female Alliance side comes off very badly in the comparison, being the side which didn't actually do anything useful, just complained. I think is an unintentional error on Blizzard's part.
By and large the pandaren starting zone was very good. Aysa should have just done something in the final sequence, justifying the idea that she is a competent person. Again, "show, don't tell". If you want players to think of Aysa as competent, you have to show Aysa being competent. As well, Ji should have been shown at least once as being obviously wrong. And finally, I think the genders of the Horde/Alliance NPCs should have been switched to weaken the link between gender and the dueling philosophies.