Speaking as someone who believes he understands the xp system a lot better than he would like to..
is not an accumlative statistic insofar as leveling. This is to say that you only end up with low xp if you node utter, utter crap. This would happen more than expected if we went to a writeup-only system.
The problem with rasing the xp requirement is that the vast majority of highly rated nodes are well, not that great. In order to recieve the number of votes you need for 100, 200+ rep, you have to talk about sex with horses or the infamous toilet seat debate for instance. There are exceptions, but they tend involve national tragedies.
That is to say the way xp works in the current system is that it punishes you for noding complete crap for numbers, but not entertaining crap. To raise the xp requirement would encoruage the creation of a lot more 'content' that was immediately funny and intresting, but not really 'For the Ages'.
Your numbers are good Professor Pi, but I think there should be more focus upon what those numbers mean in so far as these statistics.
Again, in summary: Raising the xp
requirement would encourage Noding for high rep, but not noding for the ages. Eventually this will change as the tastes and prefrences
of the e2 voting public changes, but as it is I must make the claim that it is a very bad idea.
Of course I could just be stuck up.