Few very key things in my mind that yahtzee needs to take into account when looking at overlord 2.
A) The game is a parody and makes fun of moral choice games and many other game types.
B) The game does not make mistresses a huge part of the game, one could ignore them without any major loss.
C) There is no major moral choices in the game, its brand A of evil, or brand B of evil.
D) This is not MADE as a moral choice game unlike fable, stop making it out to be one.
Now then, my two cents:
Many times, a game will put you in the shoes of this and this hero, and expect you to care about their interests, and do what that character wants. Sometimes, the game will give back story, and rewards and whatnot for you to begin to adapt those interests. Other games will not even bother.
However. Overlord is a game about being evil, and about being evil your way. You cant say, "I don't want to be evil" or, "I want to help." It says, "Your evil, and get about doing evil." It's the same as games like GTA and hell, nearly every other game out there. In GTA, you are a criminal, and you can't go good. You can't say, I don't want to ferry drugs, or I don't want to do this mission, because the story depends on it. You play the game as a criminal, and thats that. Same in every other game. You buy that game to play as this, and you play like that. Period. Overlord is the same in this respect, and in it you play as an overlord that owns mistresses.
Now Fable seems to have yanked something in Yahtzee's head, because he now seems to feel that every game has choice and you should be able to do things your way or if it deals with a moral its a moral game. Well, I'm sorry to say, many games do not incorporate choice to that extent, and if a game offers two lanes of story that so happen to deal with a moral, even if they are the same, doesn't make it a moral game.