Well, I'd argue that the meat from roadkill comes pre-tenderized, so there's at least 1 difference

That’s what I said when the cops showed up asking about my neighbor’s cat!

One massive difference is that a hunter will have observed the animal for things like ataxia or chronic wasting (prion) disease. Don't eat roadkill, it's stupid.

Toxins in the meat. Don’t eat roadkill, or meat from a bad hunter either, they can ruin a bunch of meat without knowing.

If trauma is bad then the difference is poo.