I don't understand this argument in the slightest. Dominators are Control/Damage.... Controllers are Control/Buff-Debuff. If you wish to play a Controller who takes damage powers and slots them, as I do, they're are still VERY different from Dominators, who have no buff/debuff options. You literally cannot play anything close to a Mind/FF as a Dominator, no matter what you do, simply because for a Mind/FF that slots for damage, the damage is still a 3rd option (after control and buff). You go from a Control - Buff - Damage character to a Control - Damage character, and that is completely different.
This could be play-style differences again, as if I'm going to do "lock them down and then shoot them," then I make a Dominator, not a Controller. It's true that Doms aren't doing Buff/Debuff, but then I'm rarely interested in Debuff powers - I'll lock the enemy down, I'll shoot at them, or I'll buff my team, but I generally think that Debuff just takes too darn long. Don't get me wrong, when you're up against an AV, they're golden (a good Rad/Rad makes an ITF run
much smoother at several points), but most of the time such characters just frustrated me trying to play them.
Repulsion Bomb is a 100% Knockdown power, that is a really nice control to have, and it also will Stun 40% of the minions that it hits. While it's a damage power, it does enough control compared to not-great damage, that it's more in the mode of Terrify... a power that pretty evenly split between control and damage. And more control = less incoming damage.
So, basically, Repulsion Bomb = less incoming damage to the team, both through faster mob defeats and through knockdown/stun effects. How does that not fit into a support character's concept? Now, if it were like Fire Breath, with pure damage and no mitigation, there may be a point to skipping it (although there is still the point about more outgoing damage --> less incoming damage). But it's not. It has a major control component.
If you were to say "I just don't like the power", it's one thing. We're accepting of personal build choices here. What I don't get is your argument that a 100% knockdown power is not useful for a damage-mitigating support character, while you're trying to squeeze out the last 2 or 4% of Recovery bonus for a character that won't be attacking all that much (when attacks are what use up most of the Endurance). It's as if you've decided "I'll make a support-ONLY character even if taking a support-damage power would actually make me better at support... I don't want damage powers at all, without regard to how useful they may be at mitigating incoming damage". At which point I have to ask... why not skip Terrify, then? It does damage, after all.
I've revisited Repulsion Bomb and taken a closer look at it (not for the thousandth time, I wish I could just test these in a live environment and see how they work firsthand), and swapped out Detention Field and Telekinesis for it. I have, however, slotted it for Stun and not Damage; I can live with it doing 40hp damage, even if, again, I don't see it as my job (for this build - my Dominator build is also being updated today and I've got
very different design goals there).