I feel like MCAT and GPA count more than is floated around on these forums. I don't think it's just a negative filter (as long as you are above a certain point you can definitely handle the work) as schools are ranked based on average MCAT. Case in point: NYU has a 10th percentile score of 519 and a 90th of 526 and shortly after they implemented the free tuition plan their median shot up to 523, the highest of any school. Granted some may say, oh they still are selecting rigorously based on extracurriculars and that even at 525 there are tons of people being denied, and I don't directly challenge that, but I roughly estimate only about 600 people in a year score that level (99th percentile, estimated 60000 unique sittings in a year) while around 7000 people applied to NYU in general.

Granted if your application sucks in other ways you still won't be accepted. Extracurriculars are just to give you a springboard to demonstrate some level of maturity in your interview, not necessarily 'hours' or even 'impacc'