Should I resubmit my application essay?

That's hard to say -- it really depends how effectively you answered the question, i.e. depicted yourself in a leadership role and showed valuable impact. I like to see a lot of Kellogg-specific research in the "growth" essay, because Kellogg doesn't have a Why Kellogg essay elsewhere so this is the only space you have to show commitment. Whether your rushed application will work with the Kellogg admissions committee or not, then, is rather hard to ascertain without reading the materials; if it feels like recycled essays for other schools, that could hurt you, but if it feels very targeted towards the nuances of Kellogg's questions, you might be able to convince them of your commitment.
If you have not already done your Kellogg interview, you might want to be sure your research is really solid in advance of that interview, just to shore up that deep sense of commitment to Kellogg.
As far as I know, they would not accept a revised essay at this stage, simply out of fairness to other applicants.

Good luck!
Margaret Strother

I should add that I have seen reapplicants who got as far as the waitlist , whose essays had very little to do with the question they were asked. I am surprised by how far they got with material that I think is so far off target. So I agree that while essays are an important part of the process, they aren't in themselves a deal-maker or deal-breaker. But we know that knowledge of Kellogg and commitment to the school are really important strategic factors, so you can use your interview to buttress that aspect of your candidacy.

Margaret Strother