NMDA

I am starting to work on my Statement of Purpose (SOP) for this coming fall's PhD applications for the Fall 2017 semester. I applied to 6 PhD programs (all top schools), but didn't get into any of them. I emailed the department head at one of the schools I applied to and asked what could have been better about my application, and he alluded to certain key courses that were lacking on my transcript. Since I received his email, I took it upon myself to take a bunch of classes that were lacking on my transcript and increase my competitiveness for this fall's application. There's already a topic on whether or not one should mention failures in the SOP; however, should I mention failing to get into PhD programs last year and how I improved since last year? On one hand, this could appear as I am very motivated to keep pursuing the PhD (I didn't quit after not being accepted last year), and on the other hand, mentioning that I had previously applied to PhD programs and was not accepted to any may tarnish my application.