OK, I just have to chime in here even though I have no first-hand experience of getting off of waitlists. However, if there's anything this past application cycle has taught me - it's that there isn't really a formula to getting admitted to business school.
I don't think Leverandon should be thinking about what it is that the admissions committee wants to hear at all. Unless Darden Admissions has dropped a hint or anything about potential areas of concern, it's impossible to get a sense of where an application might be "lacking." Maybe Leverandon's too young, maybe there were a lot of applicants with experience similar to his (unlikely, but not impossible) - who knows! It's the last thing you want to do, draw additional scrutiny towards aspects of your application that might be perceived negatively. The best course to follow is really what Raabend suggested - follow their instructions to a T and in a broader sense make a pitch about why Darden is the best school for you and why you will succeed there.
My own application experience is admittedly based on the four schools I applied to, so take my opinions with a grain of salt. However, all this emphasis on extracurricular involvement and leadership within and outside the workplace is hugely exaggerated. I did not have any extracurricular involvement anywhere outside of college, heck even during college I was working part-time throughout and was not involved in clubs or community service or such. "Leadership" is such a subjective concept, that I personally find it rather ridiculous it's given so much importance. Not to take anything away from those who have genuinely impressive leadership stories from their time in the armed forces or managing large and diverse teams, but whenever I was faced with a question about my leadership experience in interviews, I chose to deflect it and responded instance with instances of where I had exercised "thought leadership" - and that gave me a card to talk about anything at all, really. In any case, Leverandon's teaching experience gives him more than enough material to cover that "leadership" front.
In my own experience, "leadership" and "extracurriculars" will not make or break an application. Neither will a 44Q on the GMAT. There is enough evidence of that on these boards.