I'm probably not the best to answer, only had one Dominator but don't seem to have the build anymore. It was an Ice/Ice Dom. I would aim for perma-Hasten, perma-Domination, +tohit/accuracy and damage. Close to S/L softcap (35-40ish%) so that unenhanced -tohit debuff from powers will bring you to equivalent softcap. Mace Mastery would probably help you more than Ice Mastery and will give your stoner an amigo to kill stuff with. Smite would be one of your highest dps attacks. Moonbeam probably won't do you a whole lot of good unless the build is for i24. I wouldn't bother with heals, maybe just Destiny, Rebirth Radial.