To boil the purpose of my post down: I’m a BM, I want to use exotic pets, I mostly just do rated pvp, and there is no exotic pet that you want to use in rated pvp since you have to use a mortal wounds pet and since Devilsaur lust is not useable in rated pvp. I do appreciate the pet lists though!
For PvP (arenas) BM hunter actually brings a lot of utility if they play with a teammate who has an MS. Give running with an Arms / WW / Rogue a try and use your spirit beast.
Your biggest advantage to using a Spirit Beast in PvP as BM is having spirit mend, which heals for a crap ton and you can macro to use it on allies to save them as well as gaining access to a 10 sec cooldown purge from the spirit beast (similar to DH Purge). You do give up having Masters Call for freedom, but you gain another 20% wall so it’s a trade off.