A controller damage build will out do a dominator one cause of containment.
The average dom possibly does a bit more than the average controller, but if a Min/Maxer was after a high damage toon they'd pick a controller over a dominator.
Certain powersets can be quite high damage, Mind Primary, Fire and En secondry for evamaple, Grav Primary for single target damage
"Well, they found my diary today.
They were appropriately appalled
at the discovery of the eight victims
They're now putting it all together.
Women wrapped in silk
with one leg missing
Eight legs, one body, silk,
spider, brilliant!"
Controller damage builds can outdamage most everything in the game at high levels. I do think all dominators outdamage a vast majority of controllers, though. Especially as it seems to me that a vast majority of controllers has empathy secondary 
If you're looking for a damage dealer, you will be disappointed. Except maybe with Fire, but there you may be disappointed at the control.
For high damage pick a controller with Kinetics, Rad or TA secondary.
I really should do something about this signature.
I'd say dom's do more direct damage than controllers (execpt illusion I expect)
however controllers have the buffs/debuffs from the defenders which allows them to do more practial damage than a dom & buffs/debuffs are more team friendly.
Rad and Kin are especially good for damage output, but how good is the damage output on a ice/forcefeild controller?
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but how good is the damage output on a ice/forcefeild controller?
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Speaking as a lvl 50 Ice/FF controller I can tell you - terrible. Till you get your epics, then you become a WMD!
haven't played doms much (not past lvl 6) was wondering how much damage they do? is it more then controllers?