I've been on a somewhat similar wavelength as OP for quite some time on this site. My position differs in some key ways OP might want to consider though:
1. I don't care (so much) that some schools want 520 students and other schools are "less picky". I do care that 50% of applications to any school can be thrown out right away because every single one of those applicants does not have any kind of realistic shot at that medical school or medical school in general. This strikes me as a somewhat slimy way for medical schools to generate a small revenue stream from misinformed, misguided, or ignorant applicants.
Schools should be honest about their expectations. If you don't want anyone below 515 in your class, don't accept applications from anyone with less than a 515 and make that knowledge perfectly clear on AMCAS or your webpage. Save our time and yours, adcoms. Afraid you're going to lose those "diamonds in the rough"? I'm sure there are more than enough polished diamonds in the applicant pool that nobody will really notice and those "diamonds in the rough" will get a chance to shine at schools with less stringent expectations. What I'm advocating for is a transparent P/F line for each school, decided by the school itself. After that bar, MCAT scores simply arent considered (erased, even, from the application entirely) and the admissions committee must attempt to be more holistic.
2. Consider the consequences of creating such a system. The reality is that most applicants are very similar, even those at the very top of the
LizzyM foodchain (or, as
@LizzyM knows them, the students she actually meets at the interview). Implementing a P/F bar for academic metrics on a largely homogenous applicant pool will not necessarily mean that admissions becomes more holistic; rather, it might mean that admissions becomes more
arbitrary with undergrad pedigree and ECs becoming more important. A gap year might become even
more common than it already is because it might become too difficult to truly differentiate yourself during the undergrad years alone. Gap years are already becoming more common, but we should think as to whether we should make an already long training pipeline even longer and potentially more expensive.
Personally, I think the differences between a 515 and 523 will be ultimately miniscule in terms of their ability to succeed in medical school, match, and eventually practice medicine (and I believe the research bears this out as well), but there are a significant number of schools where that gap is the difference between going from the printer to the shredder or an adcom's desk. We should all feel at least a little embarrassed about how ridiculous this process can be.
Ultimately, no change at the admissions level will really change the quality or kinds of doctors we produce. Those changes happen at the level of undergraduate and graduate medical education, incentives and reimbursements schemes for practicing physicians, debt financing mechanisms, costs of education. That is, material conditions within and without the physician workforce determine the kinds and quality of physicians we produce, not admissions. The job of admissions is essentially to check that someone has the constitution and base aptitude for medicine, is capable of succeeding in medical school, and is a dependable individual. We should, however, continue to ask ourselves how we can go about rationally gatekeeping medicine and I'd like it for programs to be more honest than they are with their potential students.