After some months now, I have lastly found the one point in the rules which I don't like:
couldn't you have named them "Ordinary Horse"? Who wants to have "Bad" troops in his army?
As Rod says, we considered a lot of different names. In the end simplicity and clarity won out over political correctness and trying to avoid offense against individual troop types that might well have objected to the nomenclature. "Mediocre Horse" might be more accurate, but "Bad Horse" is three syllables shorter.