What's the purpose of removing some crests people got from before 6.0, while letting others keep their exploited ones? You also left survivals, kills and timed runs achievements untouched along with mount drops. I don't really see how this action serves any purpose, is fair to the player community or mitigates the damage from the exploit.
Maybe next time think about the action you are going to take, and weigh them before just *doing something* for the appearances, just removing legit stuff while letting some exploiters keep their ill gains is just unfair, especially considering how long it took to fix and how getting around the exploit required you to jump around extra steps like getting out of instance to respec.
I hope you do better with your further investigations, return the things that weren't gained with exploits and remove all the benefits people made out of it.