in reply to XP and level balancing
I would check the trend in the avg reputation per post before saying that posts are getting more votes and more people equates to faster transition up the XP ladder. AFAIK though I haven't been here that long the $NORM hasn't changed much from a value of about 11.(1)(2) At least as far as I can tell in the last few weeks a smaller percentage of posts are getting the votes. Also more perlmonks users will not necessarily translate to a higher average reputation per node or faster ride up the "level ladder" to Sainthood unless more people are voting. It is my impression that a significant proportion of uses may not be using their votes. It takes effort to go through read posts and vote on them.
I don't find it suprising that there are more level 10 monks then level 9. Sainthood seems to represent an end of the line as far as levels are concerned so you would expect there to be a net accumulation of users in level 10. With levels 2 to 9 there is a flow through the level to a higher level. It seems that a lot of users create a logon at level one but move on soon after possibly after finding an answer their question(s).
Anyway, at the end of the day, I think one should take the XP/level system with a grain of salt.
(1) You can check the value of $norm here near the bottom. I look it up here every so often.
(2) You can see a plot of $NORM here for the last 30 days thanks to jcwren (I believe). It would be interesting to find out whether there is still data back further then 30days