EtA: This^ needs to be read with the context that the federal gov has allocated med quotas roughly proportional to state population.
If the ratios are proportional and the universities state-lock their candidates then any given candidate from any given state has the same relative chance of getting in; the decision is made not of how many applicants to select but how to select them. Right now we have methods using numerical values (including interview score) that are easy to "standardise" between applicants for the purpose of selection.
From working in the medical field for a few years now it is pretty apparent to me that there are some shortages in specific specialties that need to be addressed and for which there are some personality traits that it appears very much are selected against. For example, I am told about 50% of psychiatry registrar positions in the state are unfilled (don't quote me on this). I wouldn't necessarily suggest that all psychiatrists have this quality, but it very much appears to me that you need a lot of patience to be able to do this job (by virtue of how assessment and management occurs in this specialty) and since we are selecting lots of Type A personalities for medicine (indirectly, by selecting those with high marks) we aren't selecting for this particular shortfall.
Potentially there could be some basis for this selection at the applicant level. I refer to the old undergraduate University of Melbourne selection criteria as an example of a system that could work; they used to have a "UMAT" pathway, an "ATAR (or ENTER)" pathway, and a mixed pathway. Qualifying through any of these pathways would grant a place.
Long story short, I am completely not in favour of all universities using the same entry pathway because we need more diversity in medicine, not less, and this is because each area of need requires different skillsets. While I am not necessarily in favour of any specific selection criteria (and there are necessarily shortcomings of specific ones, for example, the graduate entry pathways producing doctors who are older on average when they commence and thus hypothetically able to be in the workforce for fewer years), there is always a place for diversity in selection, and that is the hypothetical outcome of diversity in the cohort that is selected.