If this Dominance effect transfers over to the Trainer, it may make that COM less trashy. I’m not sure it if would be a good COM, but I think it would be passable at the very least and much more fun for niche flavor builds.
Depending on how well it works, we may no longer be as dependent on the Red Fang for Urad builds and instead taking more damage-focused options like the Cosmic Stalker, Bounty Hunter or Peregrine.
There was that one video someone posted using Dominance in the Slaughter Shaft. It worked really well as he rarely ever got targeted. So I suspect we can definitely divorce Red Fang.
It would also seem like Dominance is now much easier to trigger. However, I wonder if it will be worth going that far down when the combination of purple and red could be the new pet meta.
I truly hope so, if they had boosted Hidden Machine on the Red Fang instead of Eager To Impress it would have had a lot less bitterness towards it.
This would be a blessing. But then again, you have to spec all the way down to Dominance if you want to ditch your Red Fang. So it is kind of like a win-lose scenario there. Which some people might call a perfect compromise. 
To be fair though, as we get more skill points Hidden Machine loses more and more value it seems. And since Fast and Furryous doesn’t activate with URad, you don’t gain much by going deep in Green with Gamma. Dominance is actually is pretty good bet if you aren’t using Red Fang, and honestly I don’t see better places to put 1 point even if you were.
I actually agree with that and think you are correct on the observations about HM as a skill.
I don’t normally spec Hidden Machine in any of my builds unless it is for 3-shot FA, and I almost never run that. So anyway, just for S&G a while back I did a build centered around trying to maximize Hidden Machine without using FA or Red Fang. It just didn’t work that well in the first place, because you really need to use a Red Fang to get the benefit of Hidden Machine consistently. I tried the build with a Stalker, a Bounty Hunter, and a Thrillbot with +4 HM/+1 BG (so I even went 9/5 Hidden Machine).
Honestly, after running it several times, my conclusion was kind of, “eh, Hidden Machine maybe is not as good as I thought it was.” But maybe that conclusion is down to my playstyle, or maybe I didn’t build well enough. I dunno. In any event, I very quickly came to the conclusion that for me and my playstyle, Hidden Machine is kind of overrated and not nearly as effective as I had remembered it being - just kind of as a skill generally.
And you might be correct that it is down to the issue of having better uses of points elsewhere, especially for a Red Fang or Urad build (I state those as two separate types of builds, even though they are not necessarily different, just variants). It’s just as well to sink those points into DPS or cooldown in the Hunter tree, IMO.