Phlushot

Well you want 45% defense in each of the 3 positionals. I would expect a minimum of 3-4 slots in each toggle and 2 per passive (probably a LotG recharge + the Defense one) as a starting point. Don't forget Tough to put the two 3% defense uniques, and Weave. That should put you right around 40% defense. Last 5% is up to you... Combat Jumping/Hover/Manuevers or just focus on set bonuses.

Hm, Crushing Blow goes from a 2s cast to a 1.2s cast under Momentum. Almost half the cast time. That said it is my preferred attack to start combat with as it is the fastest attack in the set, though 2s isn't exactly "fast".

I hopped on the test server and was fooling around with a Brute. Some weirdness. Mesmerize showed like 84 average damage, but down below in the details it was 45 damage. Dominate however the average damage and the detail damage matched up.

Are you forgetting about Earth's Embrace?

Strange, in Mids it's showing Mesmerize and Dominate as the same damage but Dominate is a much shorter animation.

Ironic I was just fiddling with the same pairing over the weekend. I think the End is probably going to be... well the end. +1.2/s on your recovery is going to require constant management of your blue. +2.5 is usually what I consider to be about the break even point. Attached is where I got in my fiddling. I picked Oppressive Gloom over Cloak of Fear because it has virtually no end cost, plus you get occasional stacking with Atom Smasher to stun more than minions. I started out with Energy Melee for the stun stacking but wanted the double damage aura plus Whirling Hands' smaller radius meant stunned mobs regularly wandered outside of it. Then considered running it as a Brute because that's my go-to if I'm looking at 2x damage auras but I find I can't get resistances high enough on resistance sets with Brutes so came back to the Tanker. Tanker (Dark Armor - Radiation Melee).mbd

Actually! In the case of Spines you don't gain anything as a Tanker. The two cones are flagged so they don't increase and Spine Burst is 10ft (so increased to 15 for Tanker) but a 15ft already for Brute/Scrapper. So my recommendation would be Brute or Scrapper. Scrapper T9 is excellent. Double damage auras on Brutes scaling with Rage is excellent. Pick your poison.