Some of the comments to the previous post on Why People Hate Warlocks are getting way too specific.
People don't usually have emotional reactions to classes based on highly specific setups in PvE or PvP. They react to classes on a more general level. Take a step back, and look at the warlock from a higher vantage point.
Imagine a new Warcraft player making her first character. She asks you to tell you what the strengths and weaknesses of each class are. Are you going to tell her that warlocks can be melee-assist-trained down in Season 3 Arena? I rather doubt that.
If a new player asked me about paladins, I would say that a paladin's strengths were that they were hard to kill, could heal, and had great buffs. Their weaknesses are lower damage and almost zero ranged options.
What can you honestly say for warlocks? The only downside I can come up with that warlocks are fairly complex to play.* And while that's a downside for a new player, it is not a weakness for the class as a whole.
Again, I'm not saying that warlocks are too strong. Just that they lack obvious weaknesses, and that provokes an emotional response from the other classes who do have weaknesses.
*As an aside, that's one of the reasons I don't really like warlocks for high end PvE. All that marvelous complexity gets shafted in favour of spamming Shadow Bolts.