I think what people are failing to understand here is that WoW actually allows a large number of 3rd party addons so it's not really a valid comparison. The number of prohibited addons seems to be mostly limited to farming bots and things that would allow the warring factions to easily communicate with each other in game. So SE would be doing themselves a huge disservice to try to use punkbuster or some releated technology without first providing the addon framework themselves.