Dear CharlesInCharge,
It is best not to assume the reason you have been waitlisted and throw a bunch of random things at the admissions office. Your best course of action is to contact the admissions office to inquire as to why you are on the waitlist and what you can do to strengthen your application. You want to directly address their concern(s), so you are, in essence, giving them a reason to believe you are worth a seat. Depending on the reason, you might want to submit another recommendation or write an additional essay. The admissions office might also tell you specifically what you need to do. I agree that it is not your GMAT score and not worth retaking it. Once you know where you stand, then you can decide on the best way to address their concern(s).
Good luck,
Lisa