I have to agree with DaMasta333, you should be able to change it, say you make a mistake and hit the wrong one, or as you've said, change your mind. And yes, no points should be awarded for changing your rating, that would just make it easier for people to get points easily, especially if they don't change the points earned for rating them as it is now, 2 points.
Yup. If points were given, people could just re-rate games for tons of points. I don't think there is a way to see if someone has rated a game yet so if that were to happen, things would get out of hand.
Yes, for example, I gave a game a bad rating when I found a bug in it that made the game unplayable, but as soon as the bug was fixed, the game was great. Changeable ratings would be a great idea, but there is one problem that I see. Being able to re-rate games promotes, for lack of better words, "rating spam," when users go through the site and give every game a random rating without playing the game, just for points. If changeable ratings were to be a reality, users would be able to rating spam and then change their ratings afterward, if they think that they gave a game an unfair rating. This might promote rating spam because people that want to give games fair ratings will not be worried about giving a game a random rating, since they know that they can just change it later.
