It is much easier to please an audience crafting a game in an entirely fictional setting that having elements that have real life equivalents. The trouble with games that import certain elements from real life is that the player may have a certain opinion about that aspect of the game from past experience and thus have a certain expectation of it.
What the heck am I talking about? Call of Duty 4 and it’s successor, Call of Duty: MW2 is a first person shooter in a modern setting, and both have received raving reviews. However, I can’t bring myself to enjoy the game. The trouble is that the guns sound weak and nothing in comparison to their real life counterparts they’re modeled after. All the guns in Call of Duty sound dull, monotonous and similar to one another. In comparison, the weapons in Counter-Strike sounds much better.
I’m not here to bash Call of Duty, but rather point out that the same issue wouldn’t have presented itself if the game had a fantasy or sci-fi background. I have no idea how an alien blaster is going to sound like, nor the kind of damage a +3 poison imbued sword would do, but I do know something about the sound of a M-4 firing, the ballistic properties of a 5.56mm bullet traveling over 150m, and hence have a conception of how they should be. I went into the game with that conception, and the game didn’t live up to it.