#0 - Feb. 29, 2008, 11:46 p.m.
We've recently made a change for an upcoming 2.4 PTR update that will increase the amount of targets affected by Mass Dispel to a total of 10.
Source: http://forums.worldofwarcraft.com/thread.html?topicId=4976291129&sid=1
Tbh, I'd rather seen a real buff for shadow priests, but a buff is a buff :P