Excelsius : I've only gotten to see the operation of one med school's internal admissions process. They had cutoffs like a guillitone : they would consider GPA, MCAT, ECs, LORs, URM, and personal statement, and give each applicant "points" for each category.
If you had below 77 points, that's it, you're gone. 0% chance. And, the way the scale was, if you had a low enough GPA and MCAT, you could have perfect scores on the other sections and they'd still trash your app.
Honestly, given the school did fairly consider each section and weight them, and it did have 10,000 applications for 190 spots, this seemed as fair as anything. There was no way for a committe to look at 10,000 application to find someone with 76 points who deserved a spot. If you're wondering, I had 83 points with a 36 MCAT, 3.4 GPA, and good scores for the other sections. I only made the cut by 6 points, and have not been accepted to that school yet.
Most other medical schools have a similar problem : too many applicants, and not enough time to look at all the applications. I don't really see any practical way other schools could do things much differently.
Now, if you're URM, or you're applying to your state school, the ballgame is completely different, because the cutoffs won't be nearly as high for in state applicants. Some schools may give a lot more points to ECs, so it might be possible to get an interview there.
Truth is, even after the interview, your chances are heavily affected by your grades/ECs/ect. The reason was that the interview was just more points. You could get up to 20 points from each interviewer, added to your score. The admissions committee would rank everyone by composite score, and offer acceptances based on that. Presumably, they would pretty much auto accept the applicants with the highest scores, and debate over the ones in the middle, throwing out the ones at the bottom.
That means if you applied to this school on time with a 4.0/42 and had good letters and a good personal statement, you would have so many points that only a bombed interview would prevent you from getting a de-facto auto-accept.
This is why the rare bird who actually had that kind of package generally gets an acceptance to the majority of the schools they apply to.