The OP is sonicx but the poster two above me is just sonic... confused? :huh:
Ok, putting that identity crisis aside, I have played a domination game and it did work. You didn't earn points over time like in CoD4, but it was a half-hour game and the winning team was the one that held the most critical locations (of which there where three) at the end. However, there was a twist; somewhere on the field was hidden an "RPG" and somewhere else a "rocket". If you found them both, you could tell the marshal you wanted to blow up one of the locations, and they'd hit one of their explosive do-hickies and it'd make a big bang, and everyone in the targeted building would be dead. Of course, there were re-spawns, but it meant you could take the building in a lightning attack.
I, however, stood a few metres away from one of the allied buildings with a great flanking spot looking at the only enemy building (and right across to have visual on our second building) so I could stop them even being able to leave their location, let alone get within 100 metres of either of ours. I ran out of ammo eventually...
But it was a good game. It does work, and does exist already.