I don't think we'll have a problem with system-gaming as long as nobody "wins" anything real. It's all about self-improvement. If somebody wants to lie and say they self-improved, that's their own (screwed up) business... it makes no difference to me, or anybody else. People will still be supportive of each other's efforts, even that of the liar.
Experience suggests that people will in fact game systems to win fake rewards.
I just got this random idea that people who want to become better at life could benefit from a common scale of "leveling". No, I don't mean vague Lesswrongey things like "changing your mind". I mean a set of concrete criteria like "you qualify for level 2 if you can do 5 pull-ups, have solved 30 Project Euler problems, and did 10 cold approaches". Obviously there would be separate ladders for different character classes, but not too many. Also obviously, my example was a bit too high for level 2. So I guess I really want to ask some meta questions here:
1) Do you think agreeing on a common leveling scale would be a good thing for a substantial subset of LW users? Would you feel good about leveling up and telling other people about it on LW?
2) Is there some good way to determine leveling criteria that are neither too high nor too low? Maybe make an intermediate scale of "experience points"?