PG, if you look at successful YC startups (Loopt, Reddit, Zenter) has there been any pattern in the character of the founders?
I can't imagine someone with Aaron's character leading a successful company - his history (Infogami)supports this.
Once upon a time, for hackers, it was considered a step down to work in industry. However, it's since been shown there's a lot of money to be made, and lately PG's been spreading the gospel about how entrepreneurship is the true calling of a geek. But it's just not always the case.
Anyway, even if your premise about Aaron is true, the man's already done more with his short life than almost anybody on this site. Even on the business side.
For some reason Aaron feels compelled to talk out almost every personal failing he has in public. I don't know, if the famously mercurial Steve Jobs or Larry Ellison actually recounted all of their meltdowns candidly, they might sound something like Aaron's blog.
He was "famous" in some hacker circles for winning the ArsDigita prize and for his work on RSS, he was willing to move to Cambridge for a summer and work out of an apartment with little compensation.
The really interesting part of this, though, is the personal connection Graham had with applicants before they applied to the YC program (other founders accepted by YC tell similar stories).
So maybe the lesson here is: get to know Graham personally first, then apply to YC.