Feral has always been strong in PVP. Early on you make the perfect flag carrier in WSG and later on you can tank in AV. Mangle produces crazy damage, especially in cat form against casters.
The only problem with Feral is the lack of control over your opponent in melee. Rogues can stun, warriors can stun and fear, hunters can kite. We have bash and feral charge and that's it. That being said, our ability to change forms to get out of demobilizing buffs is maddening to other classes.
People understestimate the usefuless of Natural Shapeshifter in PVP. Good druids change forms in BGs - a lot. Don't be the meatbag that is running around stuck in caster form with no mana. NG, despite being lackluster in PVE, is handy for ditching that single sticky opponent like a rogue. Here's my feral
PVP build. Balance is now also very viable in PVP. Balance gives you range which is very nice. Moonkin makes you almost as survivable as Dire Bear. Again Natural Shapeshifter is handy for going between healer and Moonkin modes - a lot. Force of Nature trumps Intensity in PVP because you can jam a caster's spellcasting with it while you light them up. Here is my
Balance build for PVP.
I hope that helps!
____________________________
Characters on Turalyon
Banestaff, 70 Feral Druid
Kinblade, 66 Arms Warrior
Banefire, 61 Affliction Warlock
Kitarrin, 40 Balance Druid
Chess, 40 Combat Swords Rogue