I followed the Strategy of player named Jnza, from american server.
1. Put your pet on Passive, and drop all traps on Wrathion. Don't worry, it won't aggro him.
2. Start the fight by attacking Wrathion from behind. Pop all CDs and deal as much damage until the Lava Blobs spawn.
3. Aggro the Lava Blobs to keep them from killing your pet. Keep your pet on Wrathion.
4. Kite the Lava Blobs in the perimeter of the section where you started the fight and keep attacking the lava blobs while deploying as many snares as you can.
5. If you find that you are having problems outrunning the blobs, take the Postehaste talent to help you outrun some of them. (i used a combination of conc shot, ice trap and glaive toss. It helps glyph disengage with the self heal). If a blob is too close, scatter shot it.
6. Wrathion will eventually warp the the middle of the room. Use the opportunity to run up the balcony where the Jade Serpent is. It is best to run past her. Ignore the blobs chasing you and just get to the end of the balcony so that you wont' get hit by Wrathions mirror damage.
7. When you see the blobs closing in - feign death and stay that way. You will see that the blobs go back to the bottom area where Wrathion is.
8. But my pet is dead! Ok. True. Let's fix that. From the spot where you feigh death(ed), cast Revive Pet.
9. At this point, the blobs should not come to the balcony, as long as you don't get close to the stairs. Wait for Wrathion to finish this phase and use this opportunity to bandage up and cast disengage a couple of times to get your health back up.
10. Once Wrathion is done playing around with his Mirror images, he will rush to the platform to the exact spot that you are standing. Attack him!
11. It is now you vs. Wrathion on the balcony. The blobs will be out of aggro range, as long as you do not get close to the stairs.
12. Careful of his AOE (dust cloud and fire effects) and attack until the next Mirror Image phase. Remember to run to the end of the balcony and feign death during that phase. Even if it means that your pet will be sacrificed. Let it die. You can always revive it at the edge of the blacony.
Keep this up and the encounter will end with your victory.
Enjoy your pretty cloak.
Piece of cake. TY Jinza