JameUW,
You asked for feedback and here is mine for what it is worth (probably less than the proverbial internet 2 cents).
Based only on your PS it looks like you are in a really tough position.
But, as usual, I agree with Q [

anyone notice that Q's just about always right?

] about the tone of your PS and the need for a unifying theme.
Correct me if I am wrong, but your first 2 paragraphs suggest that you have regret and are requesting a second chance. It also seems that that is something you want to say in your PS. So, the problem seems to be to find a way to account for that with a different attitude / tone.
[Assuming that you still want to address this part]
Here are some proposals (thinking out loud) about possible ways to go about changing the tone, which are probably really basic and obvious. They are just proposals (not advice) offered because you asked for feedback.
First, the regret. Errors are basically unforeseen outcomes. Everyone makes errors, even the best. Happens to everyone. Your withdrawal was presummably unforeseen. Would you call it an error? Some errors are under individual's control and some errors are beyond individual's control. The errors
'in control' can be accounted for if whatever caused them is changed; similarly with external factors if some measures are taken etc.
Sorta basic, but I'm really trying to account for the agency here head on and directly. Your first draft PS basically does this in attributing the withdrawal to a bad fit in learning style, personality, and goals.
Is it possible to be more concrete / direct here in terms of what exactly the mismatch was; e.g., problem based versus other curricula, specificity in the personality mismatch, and specificity of school mission versus your specific goal. Addressing those kinds of things could suggest you won't withdraw again (which presummably is
the major concern). You PS mentions your goals; so perhaps this suggests a unifying theme (as Q posts).
Second, the second chance part. Did withdrawing strengthen your convictions about your goals? Did it teach you something about who you are? Did you 'grow' in some way as a result? In other words, did you learn something from it; and has that made you a
better candidate then you were before (after all you were good enough to get in the first time and this process has changed you in someway that is presummably for the positive). Put another way, will you ultimately be a better physician because you withdrew before? If so how and why?
Your first draft PS seems to have said this things already, so it seems as if you are most of the way there.
As I said previously, your position looks likes it is tough one to be in. So, I hope this helps.
nontrad314