I think I pretty much covered that with the first line, but maybe I was being to obtuse.
Doesn't that just imply the game kind of sucked to start with, if it's that easy to make it more fun by modifying it? I've had my share of fun with game modding, but really, the games I really like, I haven't got the slightest urge to do anything about, because there's no point. A good game is a totality, and you can't just change around the details without ruining the whole thing.