I hit level 90 in Townlong Steppes. Townlong Steppes is a little more linear than the preceding zone, but it's also fairly short. The storyline zone was a little confusing to me midway through. I think the zone storyline actually starts in the Shado-Pan Monastery instance. As I have not done any instances yet (45 min wait for healers!), the storyline made me wonder if I had skipped a hub somewhere.
Otherwise it's a good zone. I like the Shado-Pan. I like how the story took a bit of darker tone from the earlier zones.
The Sha are interesting villains. The one problem I have with them is that they are very interchangeable. I can never remember exactly which Sha I'm currently fighting. Is it Hatred, Despair, Fear, or Anger? Half the time, it's like, "Didn't I kill this Sha in the previous zone? No, wait, that was other negative emotion."
It's funny. There's a 45 minute wait for healers to get into the leveling instances. The queue for Coren Direbrew, on the the other hand, is instant. I tried it a couple times at level 89, and quickly realized why that was so. Healing is harsh, especially in pathetic gear. I tried at 90 and it went much better.
Mana is very harsh when you're just starting. You can't even afford to spam Holy Light. Instead, you have to be very conservative with mana, and use cooldowns aggressively. I like Execution Sentence particularly. Double Sacrifice with Clemency is also a life-saver. Also stand somewhat near the tank so she can pick up adds from you.
The first time I killed Coren, I had a shadow priest roll need and beat me on the healing trinket. It was very annoying. Honestly, if you're too scared to heal, you should let the person who actually did the work get the trinket. And don't offer "needing to gear up" as an excuse. I'm doing this in the i408 purchased green gear and a couple quest greens.
Eternal Flame vs Sacred Shield
I've changed my mind on Eternal Flame after trying it out. One important thing about EF is that it transfers through Beacon (at 50%). So if you combine it with Divine Purpose, you can often have multiple Eternal Flames running at the same time, especially if you get a good string of Divine Purpose procs. Then you can blanket the group with EF and the tank gets a huge buffer of heals.
It's very stabilizing. Can't really guarantee that it will happen, but it did often enough. The only thing you have to watch out for is making sure that you don't cast EF on the same person twice in a row.