Besides, the MU isn't an exact reversal of good and evil, as noted by Rom.
Indeed, in some respects it's possible everyone is the same as they are in the Prime Universe and it's just humanity which is evil. Enterprise seemed to go with that idea, and in TOS the Mirror Halkans were the same, though the Vulcans apparently became badass mofos who scared the shit out of Sulu. In DS9 the Ferengi are polar opposites, while the Bajorans seem to be more militant and less spiritual. Aside from forming an alliance and working together, there doesn't seem to be anything different about the Klingons or Cardassians.