Sorry if this is a repost, but here's an easy way to get through the locked doors in Isle of Thunder.
You will need a friend on a different realm. Alternatively, you can make another account to do this trick.
Step 1. Find a door in front of door.
Step 2. Walk forward into the locked door.
Step 3. While walking, have a friend (or your new account) send you a party invite to a different realm, and accept it.
Step 4. As the new server loads, the door will disappear briefly, allowing you to bypass it.
Step 5. You can leave the party to phase through another door.
This works for most doors which can be unlocked, including the ones in Guo-Lai Halls.
Enjoy exploring