A rogue can start a 2v2 arena match with a sap on the cc target, a stunlock on the kill target, he can then blind the cc target after the sap expires/is trinketed (yes, sometimes trinketing a sap is the right call), and now he can follow all that up with a smoke bomb that prevents the cc target from assisting the kill target after the sap and blind are over. And of course the sap, blind and smoke bomb are all non-dispellable. That's a pretty devastating opener.
A rogue can also reach into his bag of tricks and pull out a disarm if need be, and sub rogues have a shadowstep ability which is far superior to feral charge. If, in spite of all this, the fight turns against the rogue, he has a great ability to reset with cloak/vanishes.
About the only thing a feral has in common with that is that he also starts the arena match stealthed. The only time he gets an effective cc is when he gets 5 combo points on the kill target and uses a finishing move, at which time he can fire off an instant cyclone. But there's a long windup time for that, giving the other team plenty of time to anticipate and counter it. He can use instant roots as well, but they break at the drop of a hat now.
What ferals do now bring to the table is DAMAGE. No doubt, ferals do more damage than rogues now, and bleed damage is especially potent in pvp because AFAIK dwarves are the only ones who can dispel it. But I think anyone objective can agree that feral damage NEEDS to be higher in pvp than rogue damage, so I think allowing ferals to do so much damage with bleeds was exactly what the spec needed to be viable.
Now, it's certainly possible that feral bleed damage can be adjusted a bit downward, but it needs to be really strong damage because that's basically all that the spec brings to the table now. Boomkins remain weak in pvp and resto druids are a shell of their former selves, so feral is pretty much it for a powerful pvp druid spec.