A friend ran this idea by me the other day. Perhaps adding an additional affix when you go 16+ or something and mobs actually aggro when you CC them. Could make things interesting on Fortified.
Mobs used to get pulled if CC'd one of their comrades (save Improved Sap) from Vanilla to WoTLK. But after an entire expansion of Wrath where no one used CC + the LFG system, Blizz tried to alievate the transition of harder dungeons in Cata after the complaints.