I just finished this quest solo and found it rather easy after learning for the first time to use the orb before starting the fight with Thrall.
Here are some tips for those new to this like me:
The orb is part of the new upgrade tree in the heart chamber. It is the first trait you learn and you can only use the orb while out of combat. Also when you use it wait 10 seconds until the orb completes.
Second tip buy [Draenic Invisibility Potion] and skip all the mobs so you can kill the two guards in front of Thrall in order to get access to Thrall. Then use the orb and stand still till it completes and then go kill Thrall.
I was disappointed that the reward was a measly +2 ilvl upgrade on my cloak!? Really Blizzard only +2? Do we also only get +2 with the rest of the quests?