That's why I picked it too. I was on my 13th and final life for heroic completionist when I lost interest in the game. When I came back Warlocks had been added (and already were finished being fully nerfed by then), but they were still by far the easiest class to play at the time. I have been playing one ever since (other than 10 iconic lives that have been scattered here and there in between). It was so refreshing to finally have a class that was easy to play with unlimited magical damage without running out of spell points along with Ddoor, teleport, invisibility, and possibly knock if you were willing to pick the pact that had it.
Since then, based on what people have reported on the forums, every class has become easy to play. Now most everyone has self-healing and heroics are supposedly easy for all classes to get through (I haven't played any class through heroics other than Warlock in nearly 10 years, so I cannot verify this myself). So at this point, there is no need to continue to make Warlock's single target blast so weak. I understand that when they are doing AOE there is a need to keep them from being too strong so they don't wipe out whole groups like Sorcerers do. But when they switch to single target they should be doing at least as much damage as a ranged class and possibly more since the max distance they can hit a monster is much shorter and the monster needs to be sitting still or the attack misses anyway. So while technically a ranged attack, it faces some of the same problems melee players have (the need to be closer and the need for the target to be relatively still).