My update...
I met with HDS admissions Thursday, concerning my application.
What I was told was that there was a 10% increase in applications this year, and that most of the applicants are "self-selecting", which apparently means that they have the credentials to go pretty much anywhere, but all choose to apply to Harvard, therefore, even though they have a 50% admissions rate, it is still a competitive applicant pool. In regards to my specific application, I was told that my grades were "excellent" and it is "clear that you would thrive at Harvard", but that to make my application stronger, I should submit GRE scores and a writing sample ("to illustrate the work you could produce at HDS"). Honestly, GRE scores and the writing sample were listed as "optional"...so it kind of sucks that my application was "solid" except for the optional parts of the application. The reason I didn't submit what was "optional" the first time was that I was simply too busy taking graduate classes and teaching two undergraduate classes to revise a writing sample or study for the GRE. But, now that I'm rejected from everywhere and have nothing but time, I won't have that excuse the second time around.
I cannot tell you how heartbreaking it is to hear: "yes, you're qualified, but we just didn't choose you."