I don't see how you could ban a spec... were any hunters specs disallowed in MoP?! I also don't see how to "ban" an ability (FB is my RestoD's only threat)... might as well ban Keg Smash or a Ret's Flash Heal while we're at it.
That being said, I don't want to play with ferals. Not because they're OP, but because I'm the only person I know who was actually PLAYING feral pre-WoD. My solution: personally choose not to partner with a feral.