I knew I would succeed in medical school wherever I ended up, but unfortunately I was turned down from US schools because of my GPA. I had two BS degrees, one in business management when I was 18, and scraped by partying with a very low GPA. Then straight A's in a chemistry degree when I decided to try to go to med school in my late 20's. Unfortunately, with as competitive as US med schools are, I got immediately filtered out and never got a fair shot.
Ross gave me that shot, and I went down there dedicated and determined. They didn't hold my hand, and no, administration doesn't care one way or another if you fail out or not. But the professors do. They're all US-educated PhD's in their specialized fields, and wanted a change of pace.
I got through my time in medical school, watched several friends fail out. Not because they weren't smart enough, but because they were entitled 23 year olds who had never been away from home, suddenly thrown onto a caribbean island by themselves and partied, slept around, and didn't take it seriously. Those type of people are viewed as dollar signs in Ross administration's eyes...and I can't blame them, they are for profit after all.
But to answer your question...there weren't a tremendous amount of hurdles, I don't think. We had to pay more to take all the USMLE exams, and fill out the ECFMG stuff. Aside from that, I filled out the same ERAS application, got the same LOR's, and wrote the same personal statement as everyone else. Sure, I probably wouldn't have applied at 61 places with my score if I were a US graduate...but at the end of the day any hurdles I had to go through were worth it. Residency is Residency, regardless of where you went to school.
PS: At what point did FM, IM, and Psych become if you "only" want them fields? The only reason they are less competitive is that the pay is less. If FM doctors were bringing in 400-500k a year, I guarantee it would jump up to "competitive" specialty. Just like if dermatology paid 150k a year, nobody would want to do it. When did medicine become about who can make the most amount of money for the least amount of work, and less about following your passion?