I think c-rpg has a pretty good mix of native and realism when it comes to horse bumping. Native is ridiculous how you basically do no damage when you horse bump (not to mention how lame it is to be full speed gallop and come to a dead stop when you hit a teammate). But to an un-armored person, a horse running you over would most likely kill you (depending on where the hooves landed).
Also, when a horse dies in c-rpg it "disappears" from existence (besides the graphic). In real life just because you killed a horse running full speed at you doesn't mean you're in the clear. That rag doll body is now flying at you.