Rogues do lots of damage. Period.
Warlocks impose nasty status conditions on their victims and oftentimes are a sort of one-target controller. They also do this at range, which is safer. Thus, less pure HP damage.
Its balanced -- both do their job, they just do it differently.
See I don't agree. The rogue is better then the warlock in his assigned role. Since 4th is a game about playing as part of a team performing your role is paramount.
Combat advantage is most often granted by flanking. It's that simple. There are other ways to get it but most often you get it from flanking. As most parties have a defender having at least one other party member to flank with is a virtual guarantee. If you have a warlord it gets better. It is not that hard for a good party to make sure the rogue has combat advantage. He should have it at least 3/4 of the time by my estimation. That's only backed up by anecdotal evidence of course.
Rogue at wills allow the rogue to perform a useful functions regardless of what the DM does. The rogues at-will powers let him: move, attack reflex (but still keep his dagger to hit bonus), discourage the opponent from attacking, or do more damage. The DM has little recourse under the rules to prevent the rogue from doing his nifty little side effects.
Compare hellish rebuke to Riposte strike. The two most evenly matched powers in the game in terms of effect. The big differences are: the rogue only has to be attacked to provoke the effect while the warlock has to take damage, the warlock has to take damage from any source while the rogue only gets his damage if the target of the attack attacks him, the rogue is using a weapon so can apply feats to increase damage and the like while the warlock can only apply Astral fire if he has a 13 Dex. All in all I would say it is a wash. Now consider that Riposte strike is widely considered to be the least useful Rogue at-will.
What nasty status conditions? Are there any status conditions that a warlock can inflict with an at-will that a DM can't simply ignore by ignoring the warlock? Let's take Witchfire (warlock encounter 1) versus Dazing strike (Rogue encounter 1). Let us further assume that the warlock player chose this power because he was a feylock and got the extra bonus. That means he attacks reflex (worth a +2 bonus based on monster average defenses) and does 2d6+1d6(curse)+Cha damage. We will assume he is a smart warlock and didn't use his power on some one behind cover. The monster he hits get a -5 to attack (if the 'lock has a 16 Int) until the end of the warlock's next turn. That means for 1 attack the monster probably won't hit unless the DM rolls pretty well. It can still move though and isn't any more vulnerable to further attack.
The rogue is also a smart player so he makes sure one of his buddies gives him a flank or better yet races up to a monster that hasn't acted on the first turn. This gives him combat advantage. He pulls out dazing strike with his short sword. He has +3 to hit for using a short sword. That means even though he is attacking AC he still has a net +1 over the warlock because Ref only lags 2 points behind. He also has the +2 for combat advantage though. We assume he hits though same as the warlock. He does 1d6+2d8(pretty much all rogues take backstabber)+Dex damage. Then he dazes the target. Daze says that you grant combat advantage, can only take one action, can't take immediate or opportunity actions and can't flank. Like the -5 to attack the daze lasts until the end of the rogues next turn.
Which do you think is better? -5 to attack or daze? The damage is comparable with a slight edge to the rogue. The -5 only slightly frustrates my DM as he can still maneuver and still make the monster get in our way. The daze really tworks him off though. For one thing the rogue gets combat advantage
again on his next turn. The monster is no longer acting to block a path to the juicy targets in the back (No OA). He can't move and attack so he can't get into a better position. Best of all if another teammate decides to whack the target he also gets combat advantage.
Best of all who was the better controller? Who made the monsters not do what they wanted and who was merely an annoyance?
I don't see either of these situations as uncommon. The rogue does more damage and got a better debuff on the monster. He is just better at the role of striker. Who cares if the Warlock is a better controller? The wizard is his daddy as a controller.