During the filming of Waterloo (1970) which featured thousands of trained extras (who were actual soldiers), the cavalry charges caused the infantry to rout time and time again despite there being no threat of the horses actually colliding with them, and the scene had to be scrapped. No matter how little danger you are actually in, the cavalry charge itself is enough to cause infantry to break up. And yes, infantrymen would sometimes stand their ground, and in that case the infantry would often retreat. This is why images like this:
are so ridiculous, because that would be a worst case scenario for both sides and only a robot would commit to a charge like that.
Multiplayer matches can never hope to simulate morale like that, so trying to make cavalry more realistic is already missing the main component for that.