I think that it would be a good idea to be able to change your game rating after you've rated a game. Sometimes your idea of a game can change.
I think this would be cool. Some people will probably say it is not necessary though. I know it is not on the list of priorities because of the AG optimization.
It would be nice. I bet that a lot of people gave Colony a .5 just because of the servers crashing, but now that they've fixed that the people can't change it. I guess you shouldn't vote until you're entirely sure though.
This would be awesome. I originally rated Bubble Tanks 2 a 5 but I always wanted to change it to a deserved 9. It was even on my favorites list even with this 5.
It's very useful for mistakes too. I wanted to rate Colony a 10 but I accidentally clicked 9. I rated Sonny 2 a 10 but I think it now deserves a 8.5 or something like that.
Really, opinions change over time. Great suggestion, though suggested before.