I never had to write a re-applicant essay, so others may be of more help, but I'll give you a few pointers.
I would cut out anything pointing out that you were a "failure" or that you thought you were. You talked about that for a couple of sentences, and while the introspection was great and allowed you to grow, this is the first thing that you talk about in your essay, which sets up a negative tone automatically. I want to hear about your successes, right off the bat! Maybe include more about this near the end of your essay? Talk directly about your other improvements and how these helped you deal with challenges and not accepting failures (although choose a less negative word).
"At one point, I justified an MS in Human Physiology before reapplying. However, speaking with Dr. Katherine Mellen and Mr. Byron Bork helped rationalize my situation to focus on directly strengthening my application, rather than seeking alternate routes or a shortcut." I'm not sure if I would include that you thought your idea was irrational at one point. It makes you seem a little unsure about your DPT. You could mention that they were great mentors who helped you succeed in strengthening your application, but no need to mention that you once had an idea that didn't work out. I get that you're trying to show how committed you were to improving your application though.
"I even had a perfect exam score in Human Anatomy and was within the top 5% of my classes." This sounds a little braggy and pretty weak to me. How many people were in the classes and how do you even know you were at the top 5%? Was the exam only on chapter 1 stuff? I might be too nit-picky here, but these were my thoughts. I think just mentioning your huge improvement in grades is enough to show that you can understand difficult material.
"Previously with class, I worked 8hrs/week at Tropical Smoothie." I would remove this. It seems out of place and seems weak after you just wrote how much you worked at various jobs.
I love the clinical experience paragraph!
And I'm not sure if this would help:
http://dptknow.wix.com/dptknow#!tackle-the-reapplicant-essay/c1knk