This game is city of AOE not city of snooze single target dmg. Mind is an old set and just doesn't compare to the other primaries on a dominator. When everyone is an incarnate level shifted with IOs mind doesn't offer anything more than what another primary can do when all you want to do is delete a spawn with your powers.
You have blasters with the mentality of kill or be killed with nukes up every other spawn. You have scrapper and brutes able to decimate in melee, heck even tankers got a damage buff. Basically this game has gotten so much power creep that everyone wants to just aoe spawns instantly so putting a spawn to sleep in order for you to single target something down safely is something you'll never ever see teams following.
So the best Dominators who can one shot cc a group to deny their alpha strike are the ones you want to play and match it with the secondaries that do the most damage.
Plant , Dark, Earth all have very fast recharging and fast acting abilities to shut down a spawn so you can go about destroying them.
Fire has bonfire which is just broken by adding a simple IO to it.
Electric takes a multi prong approach with a pulsing sleep, chaining confuse and end drain. In essence elec will shut down a group in time but won't be so successful with completely denying attacks until some time passes.
Gravity has wormhole but that takes eons to activate at 3 seconds or so. A blaster would have nuked that spawn dead before you even finished the ability. Gravity is only good as a controller because of the impact mechanic but as a dominator you have your assault secondaries that just make that advantage a wash.
Ice has no benefit in being a dominator over a controller. Arctic air after the proc rules are a pale comparison to the beast that it was when the purple proc used to go off more frequently thereby securing it's role as a top controller. Now it's in the bottom barrel like mind control.
Mind is a shadow of it's former self. Dark is the new kid in school who is cooler, edgier and better in control and damage. This set I wouldn't ever touch until control set gets their aoe holds unprunned .
I just don't get the appeal of mind or ice when you have the big bad 3 of plant Dark and fire as a choice .