I for one with my T4ish gear, will attest that you cannot properly gauge Affliction on testing dummies, and expect good results.
Flatly put I noticed a 300 DPS increase when I switched from dummies to actual bosses. My spec is 56/0/5 with the Death's Embrace talented out. That talent does pay off on bosses in the long run. I'll state flatly most bosses die in under three minutes, and I think they need to adjust Affliction DoTs to tick faster. Speeding up the rate at which they tick is perhaps the only way to balance us out with the other classes on trash and short lived bosses especially.
I can't see level 80 content right now but I can tell without a doubt Affliction does significant damage, as does demonology, and destruction. What I don't see is the rotation being simple for Warlocks. In the Affliction tree you should have a degree in spell weaving, and in the Destruction tree you need a doctorate in it. You just have to know what to hit when depending on the number of variables up at any given moment - this adds a lot of "skill" to the class - but at the same time makes me feel like Blizzard class designers did this just as a wink and nod to the "One button Warlock" etc.
The one button Warlock days are clearly over, but the direction the class has gone in is unusual, but I will not say it is cruel. At 80 I think things will balance out.
So short version: Yes, Affliction damage takes some time, you are effed on trash, and at level 80 you should see nice figures.
I found this nice post on Eradication, and as to why so many Wotlk locks are speccing into only one point of it...
MMO-Champion BlueTracker - Eradication needs changed. Blue please read.