I doubled in a hard science major at a very good undergrad and did very well. Knew tons of premeds, have lots of premed friends, and come from a family of doctors. I just want to address a few things re: medicine as an ideal profession.
1) While job prospects are good out of medical schools, do not automatically assume that people with the raw scores of T14 law schools align with that of top 100 med schools (sorry, I am not taking into consideration more schools than this because I think you'd have to be a fool to attend some schools below this at sticker/without a backup plan, and equally a fool to take out ~300k in med school loans if you aren't very, very gunnerish at a top top school). While there are always dumb eggs, you can get into some shitty med schools with around a 30 MCAT and a <3.5 GPA. Yeah, you can say "oh the MCAT is harder!" (it is not, unless you suck at memorization) or "science classes are harder!" (completely subjective, especially at T5 undergrads where excelling in 'classic' humanities majors is very difficult) That said, how many people here pining for medicine can even do that? Let me put it this way: not everyone is good at science. I have friends who are naturally brilliant businesspeople/analytical thinkers who slave away at an idea of premed and fail. You can extend this line of thinking to poorly-equipped lawyers as well, but just realize that there's no guarantee.
2) Medicine is not just about GPA/MCAT. It's not uncommon for 25% of your pay to hinge upon patient reviews. Yes, there are horrific doctors out there who should be banned from practicing, at best. But it is a social profession with a moral responsibility that I think many of the K-JDs here who have never had a job do not grasp. If people can't even handle working with indigent clients in PI, I cannot even imagine them treating paranoid schizophrenic crack addicts without incessant whining. As a doctor, unless you have your own practice or are in the a chic private hospital (don't count on it), you see every single person in society. All layers. I think this can be a great thing, but it is not for everyone. You gotta work your ass off to get into a desirable sub-speciality. Do you have the work ethic or raw intelligence for that? You want to be a surgeon? Are you squeamish, are you good with your hands? Trust me, people who think they can handle surgery often crumble when faced with reality during rounds and have to choose a different speciality. Also, a 6-7 year residency+fellowship for the most prestigious positions is hardly lucrative in the 'prime of your life.'
3) I know older doctors in advanced specialities who work insane hours. You can't bank on a ROAD speciality (and do you really want to do radiology if you aren't intensely antisocial?). Visiting intensive treatment wards was one of the most emotionally crippling images I had ever seen. The idea of doing that every day does not appeal to me, personally. Can you look into people's eyes and tell them they have months to live while their family is crumbling around them, or not even there because they don't care about this person? This sounds really hyperbolic, but the doctors in my family have to do this on a weekly basis. You end up becoming very immune to this kind of emotional response to things, and I never wanted that for myself. Your milage may vary. Yes, endless paperwork sucks, but you need a special temperament to be a good doctor, and lots of regretful lawyers/bright-eyed premeds just see $$$ (rapidly diminishing, btw) and honor (you need to be honorable to deserve it).