Fear spam is the bane of warlocks. Its the reason they are hated and the best warlocks are the ones who rarely do it. Yes there are ways around it but rock/paper/scissors, there are classes that cnt stop it in time. Though as a class to play as, a warlock does have it damn easy in PvE. I play a hunter as my main, so pet tanking is useful. The fact a lock can DoT it and let the VW work makes it easy for them against most mobs. Failing that, they have other pets and omg, other spells which they can use if things get ugly.
If you wanna kill a warlock, smack him upside the head :) Just dnt get scared doing it..

The best warlocks know *when* to use it. Fear is amazingly helpful against healing classes when your felhunter's devour magic is on CD.  It's rediculous for plate and mail classes to whine about how overpowered locks are.  Get your first aid up, use it and slam them and use stuns when they try to fear.