Without knowing your preferred powers, loathed powers, etc, it's hard to be specific, but here is one example of an end-game (read: expensive) build that hits some big Dominator care-abouts: perma-Dom, perma-Hasten, multiple damage bonuses, and an AoE control (Stalagmites) that can be maintained indefinitely with Domination and/or Gather Shadows.
Soul may not be the most flashy or OMGCOSMICPOWER epic choice, but it's nicely thematic and lets you stack to-hit debuffs.
Troglobite, Earth Control/Dark Assault/Soul Mastery dominator
Villain Plan by Mids' Reborn : Hero Designer 2.6.0.1 https://github.com/ImaginaryDevelopment/imaginary-hero-designer
Click this DataLink to open the build!
Troglobite: Level 50 Mutation Dominator Primary Power Set: Earth Control Secondary Power Set: Dark Assault Power Pool: Speed Power Pool: Fighting Power Pool: Concealment Power Pool: Leaping Ancillary Pool: Soul Mastery
Villain Profile: Level 1: Fossilize
(A) Basilisk's Gaze - Accuracy/Hold
(3) Basilisk's Gaze - Recharge/Hold
(3) Basilisk's Gaze - Endurance/Recharge/Hold
(5) Basilisk's Gaze - Accuracy/Endurance/Recharge/Hold
Level 1: Dark Blast
(A) Entropic Chaos - Accuracy/Damage
(5) Entropic Chaos - Damage/Endurance
(7) Entropic Chaos - Damage/Recharge
(7) Entropic Chaos - Damage/Endurance/Recharge
(9) Entropic Chaos - Chance of Heal Self
Level 2: Smite
(A) Superior Blistering Cold - Accuracy/Damage
(9) Superior Blistering Cold - Accuracy/Damage/Endurance
(11) Superior Blistering Cold - Accuracy/Damage/Recharge
(11) Superior Blistering Cold - Damage/Endurance/Accuracy/RechargeTime
(13) Superior Blistering Cold - Recharge/Chance for Hold
Level 4: Gloom
(A) Entropic Chaos - Accuracy/Damage
(13) Entropic Chaos - Damage/Endurance
(15) Entropic Chaos - Damage/Recharge
(15) Entropic Chaos - Damage/Endurance/Recharge
(17) Entropic Chaos - Chance of Heal Self
Level 6: Quicksand
(A) Tempered Readiness - Endurance/Recharge/Slow Level 8: Stone Cages
(A) Superior Ascendency of the Dominator - Accuracy/Confused/Hold/Immobilize/Sleep/Stun/Terrorized
(17) Superior Ascendency of the Dominator - Confused/Hold/Immobilize/Sleep/Stun/Terrorized/Recharge
(19) Superior Ascendency of the Dominator - Endurance/Recharge
(19) Superior Ascendency of the Dominator - Accuracy/Confused/Hold/Immobilize/Sleep/Stun/Terrorized/Endurance
(21) Superior Ascendency of the Dominator - Accuracy/Confused/Hold/Immobilize/Sleep/Stun/Terrorized/Endurance/Recharge
(50) Superior Ascendency of the Dominator - Recharge/Chance for +Damage
Level 10: Super Speed
(A) Celerity - +Stealth Level 12: Stalagmites
(A) Absolute Amazement - Stun
(21) Absolute Amazement - Accuracy/Stun/Recharge
(23) Absolute Amazement - Accuracy/Recharge
(23) Absolute Amazement - Endurance/Stun
(25) Absolute Amazement - Chance for ToHit Debuff
Level 14: Night Fall
(A) Positron's Blast - Accuracy/Damage
(25) Positron's Blast - Damage/Recharge
(27) Positron's Blast - Damage/Range
(27) Positron's Blast - Accuracy/Damage/Endurance
(29) Positron's Blast - Chance of Damage(Energy)
Level 16: Gather Shadows
(A) Recharge Reduction IO
(29) Recharge Reduction IO
Level 18: Earthquake
(A) Dark Watcher's Despair - To Hit Debuff
(31) Dark Watcher's Despair - To Hit Debuff/Recharge
(31) Dark Watcher's Despair - To Hit Debuff/Recharge/Endurance
(31) Dark Watcher's Despair - Recharge/Endurance
Level 20: Engulfing Darkness
(A) Armageddon - Damage
(33) Armageddon - Accuracy/Damage/Recharge
(33) Armageddon - Accuracy/Recharge
(33) Armageddon - Damage/Endurance
(34) Armageddon - Chance for Fire Damage
Level 22: Hasten
(A) Recharge Reduction IO
(34) Recharge Reduction IO
Level 24: Boxing
(A) Accuracy IO Level 26: Volcanic Gasses
(A) Gladiator's Net - Accuracy/Hold
(34) Gladiator's Net - Recharge/Hold
(36) Gladiator's Net - Endurance/Recharge/Hold
(36) Gladiator's Net - Accuracy/Endurance/Recharge/Hold
(36) Gladiator's Net - Chance of Damage(Lethal)
Level 28: Grant Invisibility
(A) Luck of the Gambler - Defense/Increased Global Recharge Speed Level 30: Tough
(A) Steadfast Protection - Resistance/+Def 3%
(37) Gladiator's Armor - End/Resist
(39) Gladiator's Armor - TP Protection +3% Def (All)
Level 32: Animate Stone
(A) Sovereign Right - Resistance Bonus
(39) Expedient Reinforcement - Accuracy/Damage
(39) Expedient Reinforcement - Damage/Endurance
(40) Expedient Reinforcement - Accuracy/Damage/Recharge
(40) Expedient Reinforcement - Resist Bonus Aura for Pets
(40) Blood Mandate - Accuracy/Damage/Endurance
Level 35: Dark Embrace
(A) Gladiator's Armor - Resistance
(42) Gladiator's Armor - Resistance/Rech/End
(42) Gladiator's Armor - End/Resist
Level 38: Midnight Grasp
(A) Hecatomb - Damage
(42) Hecatomb - Accuracy/Damage/Recharge
(43) Hecatomb - Accuracy/Recharge
(43) Hecatomb - Damage/Endurance
(43) Hecatomb - Chance of Damage(Negative)
Level 41: Dark Obliteration
(A) Ragnarok - Damage
(45) Ragnarok - Accuracy/Damage/Recharge
(45) Ragnarok - Accuracy/Recharge
(45) Ragnarok - Damage/Endurance
(46) Ragnarok - Chance for Knockdown
Level 44: Soul Drain
(A) Obliteration - Damage
(46) Obliteration - Accuracy/Recharge
(46) Obliteration - Damage/Recharge
(48) Obliteration - Accuracy/Damage/Recharge
(48) Obliteration - Accuracy/Damage/Endurance/Recharge
(50) Obliteration - Chance for Smashing Damage
Level 47: Weave
(A) Luck of the Gambler - Defense/Endurance
(48) Luck of the Gambler - Defense/Endurance/Recharge
(50) Luck of the Gambler - Defense/Increased Global Recharge Speed
Level 49: Combat Jumping
(A) Luck of the Gambler - Defense/Increased Global Recharge Speed Level 1: Brawl
(A) Empty Level 1: Domination
Level 1: Prestige Power Dash