It's entering Saving Private Ryan turf a little I think, with finishing off enemy soldiers with shots at point blank range after they're down.
They already showed that in
Landing at Point Rain.
You're right, they basically did, but I believe the context was different.
In
Landing at Point Rain, a trooper shot a Geonosian who was still on fire and burning (after being hit by a flamethrower, which I'll come back to). It could plausibly have been interpreted as a mercy killing.
But in last night's episode, a trooper shot an Umbaran who was already completely incapacitated. They didn't even check him to make sure he was already dead. The trooper who shot him pronounced him dead first, at least euphemistically, but I think he might have still been moaning (and of course, why shoot someone who's certainly already dead?). It could plausibly have been interpreted as a revenge killing.
There was also a stark contrast between the atmosphere, pacing, and music of these scenes.
Now bringing out the flamethrower in
Landing at Point Rain was indeed pretty graphic. But then again, shooting Separatists with blasters and getting shot by blasters is, in general, also violent. The whole show is violent, and we really lack moral context in the majority of cases to know whether the violence is necessary. (But I think we're supposed to assume it is necessary, under the assumption that the Republic's fighting of the overall war is necessary.)
But with Anakin not around and being chipper about everything, the show seems darker. I wonder if that's on purpose. Maybe the point here is that Anakin has been behaving inappropriately cheerful in the midst of all this violence?
YMMV.