dominatrix is the anti heavy in rovers arsenal
Try using it to counter any real heavy (crab, grizzly, cyclops), and you'll learn that Domi is not antiheavy.
Rovers don't really have any real antiheavy. What they've got is a bunch of units with an anti-heavy sidearm, which, when used in mixes that are optimal for each special case, and with special tactics for each case, tend to kind of work against isolated heavies.
Like you can kite and capture Minotaurs and Ogres with Dominatrix, or theoretically swarm, slow, and melt Grizzly and Cyclops using a Dart/Scorcher mix.
Many of these fall apart if the situation becomes slightly different from what you were preparing for. One Kodachi will ruin your Cyclops dive, a couple Archers will ruin your Grizzly dive, and a sudden Cyclops will ruin your Dominatrix play.
the real question is, what to do when emissaries start to come out.
Emissaries are dirty play, so you're allowed to play dirty against them. Rovers have the Thunderbird advantage over tanks (faster speed, more dps/cost on scorchers and darts), so you can make good lasting damage if you follow-up a thunderbird strike with a rover wave attack.