At its base, fear is actually Blizzard's way of trying to come up with another game mechanic. If you're a veteran MMORPG player, you know there are three archetype classes-- healer, DPS, and tank. All three of them are centered around damage-- either getting rid of it, doing it, or tanking it. Fear, however, plays with none of those rules-- it's a complete damage negator. The reason Warlocks have fear is so they can wear cloth and yet stay alive for a long time against one target-- long enough for their DoTs to come in.
The problem with fear, however, as even the developers have admitted, is that it's not fun for the person being feared-- getting feared leaves you with almost no option but to sit there and do nothing. It removes control from your character, and that's never fun.
So how can we fix it?