Hey, This has probably already been suggested, but I think you should be able to change your rating for a game, but not get more armor points for doing so. Like it's happened to me at least twice where I accidentally mis-click and give a game a rating I didn't mean to.
This is going to be a definite change in 3.0 -- I just know it! Since many people like you and I have considered changing our previous scores after playing the game some more (or just accidentally), there could be a really good chance of that changing in 3.0.
I'm pretty sure most or the majority of The List will be added. That's my take on it at least.
I'd agree that this is a good idea. I'm glad that you thought to mention that one wouldn't get more points for doing so, because then people would just spam. Another advantage of the change would be that if you give a game a high score, but as it progressess you don't really think it's really that good after all, you can change your score to reflect your new experiences.