It's the chaining of fear. I used to play a paly, and have a rogue. The paladin's stun is on a cooldown. They simply can't chain it due to a CD, a lock can.
As to what can break fear, a lot of those things are also on cooldowns.
- A shamy has a tremor totem, however kill totem and there's a CD to caste another.
- There is fear warde, but again there's a CD
- the insignia, has a cooldown
- enrage pet and beast within (BM hunter tree, 41 pt requirement), cooldown
- pet stun (intimidation), cooldown
Fear however can be chained. Anything on a cooldown, how would one chain it? Now if they'd do one of 2 changes, it could put some balance to this. Either make it like other forms of crowd control, so that fear effects are broaken, the second damage is taken (either by a DoT or straight attack), much the same way a freeze trap, sheep, shackle, or other forms of CC is broaken. Or make a feared target regen health like a sheep does
Another quick and dirty end would be to put a universal cooldown on all a locks forms of fear (though again that might touch more on the PvE side of things, then some other things).
But what we have now is a dev, after years where characters have seen nerf after nerf apply to their class admit that it is over-powered but say
I'm not saying it's right that warlocks should be so powerful as a solo class simply because the balance is aimed somewhere else, but that's the way it is and it has been said that little to no balancing will be done for 1vs1 or 2vs2 scenarios.
Since when? And where was that argument over the years when any class has been up for a nerf prior to this post from one of the devs?
Personally, I think bliz should look at their stance in that there post, as
The bottom line is that warlocks are a powerful solo class - but I don't remember anyone claiming that they would be anything else...
could get any hunter for instance to re-visit past history and ask about what was claimed with them also. However, in all cases the decisions, to balance, or not to balance, and where, should be impartial and equitable for all classes.