I'm not saying Warlocks need to solo 2-3 people by himself with just dots, but if the Warlock on his own can't create the pressure needed for HIM on his OWN to kill SOMEONE, then you know his damage is just shit, because I bet my left nut if you let a DK or a Feral at their current state hop on someone they'll do that.
The way the class is now, I see absolutely no reason why our dots shouldn't be hovering around WotLK levels of pressure on a single target (or on multiple targets, if we can get them there).
In WotLK, dots ticked HARD on your kill target with haunt up and nightfall procs thrown in. You could wither a target very quickly with your full attention on it, especially with the drain soul execute (which was fucking amazing in wrath, to this day I have no idea why they pulled back on that mechanic). This was throttled by the fact that we had to cast as much or more than other casters and every cast exposed our main/only school to interrupts. This made it difficult and skillful to keep dots up on multiple targets and prime switches, and drain soul was a huge way a lock could separate himself from the pack (i.e. landing a 24.9% drain soul right before a heal, causing massive damage and keeping up pressure that otherwise would've disappeared). We also had only one instant CC every 90 sec (death coil). In wrath, I could fear a poorly positioned resto shaman out of his heal on the kill target, dot him up in the fear, haunt him, fear him again, and death coil blanket him, and provided I got sufficient/lucky nightfall procs, he would either be dead or blow a major CD to live. This was my favorite state of aff of all time, by far.
Cata is where this shitfest started. Soul swap, it seems, was the beginning of the end for this class. With soul swap and fel flame, it was no longer remotely as difficult to maintain rows of dots on multiple targets. Because of that, our single target pressure got gutted and we became much more of a spread-damage threat. While I think soul swap is a fucking tragedy of game design, the class overall was still acceptable to play and you could still do more things to set you apart than most classes can.
Idk what happened in MoP (sounds like shit got even more dumbed down with SS though), but it seems like now in WoD the shit has hit the fan. In a stroke of genius, they removed those extra tools we got in cata that changed the class so much. I loved fel flame as much as the next guy, but it being gone isn't really that bad, it should serve to increase the skillcap of the class to not have a crutch like that (although it's true that having no DD spell is fucking retarded, where is searing pain blizzard seriously). Then they made soul swap and SB:SS basically highly situational tools that probably won't get used too often in games the way things stand now. The result of this is that it's once again much more involved to try to maintain dots on multiple targets and spread your pressure well.
But then, in a stroke of utter retardation, they left our damage in its gutted state instead of returning it to WotLK levels of pressure. Then as if that wouldn't have been enough, they also gutted the class-defining ability of fear and deleted all other forms of control, leaving us with just the one instant CC and a nerfed interrupt. Somehow they managed to remove everything the class gained over the past 4 years but didn't return any of the strengths that made it solid back then, instead even went as far as to nerf even MORE essential stuff.
The result seems to be just this gimpy class that doesn't seem to have anything going for it. I'm really disappointed in this so far.