I've been eating many level 70 hunters and warlocks (the supposed kings of world pvp) alive with my 67 feral druid, and many of them even have at least some of the arena gear, meanwhile I am mostly in blues/greens.
Bull**** if druids don't have spell interrupts btw. Maim ftw. Just throw in your initial flurry of attacks and once that lock starts casting fear, maim him and heal yourself, and if possible break combat, stealth, and pounce again. Warlocks are extremely susceptible to burst damage while being incapable of dishing burst damage themselves (at least, not without a long cast time that is so easily interrupted.)
Hunters? What can I say, just run in close and they become cat food. You run so fast that even if you don't remove their wing clip (which you easily can) you'll still run faster than they can back away from you, and your melee attacks far outclass anything they have. Starts casting scare beast? Easy, just maim and heal yourself while your dots tick him away. If he trinkets out of that, shift to bear and bash. Save your trinket for the freeze trap. Only BM hunters can give me some trouble since I can't maim them but just be a little more creative about things and they're almost as easy.
And flight form owns any flying mount any day, the fact that it is instant cast, and the fact that it only costs us druids 7g, and includes free 225 flight training, and we can fly two levels before everybody else, is just awesome