Most of the really high rated hunters usually use not one pet, but have an entire array of pets avaible for whatever is queuing for that night.
Most high rated BM hunters have the following in their stables:
Core hound:-25% casting speed, to use against RMP
Wolf: Best used for the great AP buff it provides
Crab: Pin
Worm: -20% armor vs meleeheavy cleaves
Chimera: Slow and generally screenfilling annoyance
Now you have probable been wondering where the trick is?
Well as you can see every pet has a seperate usefull trick against most of the comps.
So if you queue while you know another high-rated team from your server is queueing, let your teammates join, check if its indeed them (by looking if their in the same arena as your team and to check if your teammates can whisper them), take the apropriate pet out of your stables to counter them an then join the game with plenty of time spare to buff.
This ofcourse also works with dualspeccing if you want to respec to a certain spec just to counter someone.
Another thing to note is that Wolf is a really lovely pet in RoV, so if your teammates see the chosen arena is RoV they can tell you so you can get your wolf out.