I really like this idea but do have some concerns about it--
(1) People who post and would contribute to such a list are probably more competitive candidates than most MPH applicants. The list may end up dissuading rather than supporting people in applying.
(2) It's really hard to capture the factors that MPH admissions committees look for since I think the SOP/other essays play a big role, and I am pretty sure everyone would rate their own personal statement highly. Test scores and GPA aren't really very helpful except in understanding what the very top schools are looking for, and those schools usually post that kind of information on their websites anyway.
I'd like to suggest some kind of document organized by school rather than applicant. There are always questions on this forum about what schools are strong in which concentrations, when deadlines are, which ones give more/less financial aid, which ones have better job outcomes, etc. Knowing reasons why past applicants chose to enroll at a school (or chose not to) would also have been very helpful to me last year.
And then finally, I think it'd make a difference if people stayed active on this forum during and after their program, if possible. Past applicants were enormously helpful to me last year, which is why I keep up with the forum this year and plan to continue as long as it's feasible for me. There are so few posters here that are in school and even fewer that are in the field. I think if we can commit to keeping this a truly supportive space (unlike soooooo many other parts of SDN/other forums), then maybe future applicants will lurk less and ask more questions.