I would argue that having onerous tests are not a great proxy. Not only do they not necessarily measure how good a physician a student would be, but it also encourages undergraduates to intentionally enter easier/less rigorous coursework to focus more on the exam aspect (though GPA plays a large role as well). I'm sure a psych major may make a fine physician, but I don't want doctors to only be educated in a rather dubious field. If undergraduate education is only a stepping stone towards medicine, then just integrate medical education with undergraduate studies, rather than adding a ritualized acquisition of a bachelor's degree.
Everyone takes the same premed courses though, and you need to be able to teach yourself any MCAT content that wasn't covered by coursework. Sure people will game it, but it's your science GPA that counts, and having people from a diversity of backgrounds is a good thing.
Nah, doesn't matter. There are still the pre-med requirements (organic chem etc -- recall recent bruhaha about that at ?NYU) that can't be sidestepped for easier courses
