Yeah i completely do agree with what Brov said. But for an arena player, i'd go with Boomy being the hardest and most complicated choice as you can LoS his abilities, which means you need to know when to cast them and when to swap into cat form. A good boomy can make their healer LoS from their damage with wild charge then spamming roots on the healer, but a feral could do that too, but just because of the damage a feral is able to pull out, it is NOT needed, your target will still die, quick. And if you see it from my perspective, the LoS healer strategy is a 9-6 second "Stun" on the healer.
However, Feral is pretty OP though, which means, if you put your brain onto it, your enemy dies, if you go yolo, your enemy still dies... (GAWSH DUDE!, i already hope Legion comes quick, i want to play my feral again and have fun)!!!