whenever they "tweak" mob code, actions, pathing, or well.. anything mob/npc related, they risk breaking pets.
and yes.. it would be great to see them finally forking out all pet code from the mob code. that way, they could infact, spend the time again to properly fix the pets, and have the fixes persist for a much longer duration.
maybe then, they could better address agg issues with pets that didnt exist years ago.