I'm personally not somebody who ever used Dominatrix, because it was too slow and unreliable for my liking. It has a big turn radius and now it'll be even harder to keep out of enemy range. I'm astonished that a unit needs a substantial (10%) nerf if I don't even have a use for it, nor see it being used by other people as a generalist unit.
I wasn't the most active player lately, but isn't the backbone of the rover factory consisting of Scorcher and Ravager? If anything one might want to increase the unit variety in the factory. That'd mean transferring powers to niche units like the Leveler, Dominatrix or Merl. It's up to discussion whether these units really need more power, but I certainly wouldn't go the other way unless there are matchups where the Dominatrix is used more than the two heavyweights first mentioned.
Regarding the axis of the nerf (speed) I also see a (possibly unintended) role-shift. For me Dominatrix was always more of an anti-heavy unit due to its long reload time and being too slow to kite raiders. A slower dominatrix will reduce its kiting ability, meaning the burst-fire (long reload) will come more into the foreground. This effectively means that the strength of the Dominatrix now lies in capturing enemies before they can damage it sufficiently. In small numbers this means it remains effective against expensive raiders like Kodachi, Blitz and Halberd. It loses effectiveness against fast, heavy units like the Reaper (Minotaur) and possibly Mace/Banisher(Ogre).
This happens because more units are able to catch up with it now, and especially in the tank factory the heavy units are those with the DPS to capitalize on closing the range. Wouldn't it be preferable to have a Rover unit that is effective against Reaper balls? Rovers already seem to lack in anti-heavy capability.