Effusion

That's also because there are few assault powers that have a reason to be used other than to fill in a rotation. Assault sets are pretty boring in that regard, especially when you consider how similar they all are.

Domination should probably have either a bar or a cooldown but not both because it makes the gap between permadom and not permadom (and slow clicks) too wide. I'd attribute the dominator's lack of value in endgame groups primarily to the lack of challenging content for fully kitted out characters devaluing crowd control, and that may be better addressed by having sufficiently challenging content due to the broader benefits it would bring to the game. Being able to set multiple abilities to autofire would be an excellent quality of life change for all archetypes though.

I've been skipping them since 2004. I don't really value their immobilize (except on illusion because it's so containment starved, but illusion doesn't get one) so I've always just looked at them as attacks and found them lacking.