Actually, it worked TOO well in ENT which is why they scrapped it. They actually had a spot open in SOAP last year for the first time in a while and I think that scared them - they didn't want to scare away competitive applicants. However, if everybody does it (or at least the small competitive fields), then it might actually be a feasible solution.
I also think a hard app limit (say ~15 per applicant?) is overblown in the effect it would have on mid/low tier students. These students are already being screened out without ever being looked at at top programs. Applying to 20 top programs is the exact same as applying to 3 if you get zero applications either way.
The problem right now is kind of akin to the problem many men have with online dating (
if you want to read more about that). Because the risk of not matching is associated with such devastating consequences, even very competitive applicants are sending tons of what could be considered "safety" applications. So every program in small competitive specialties, even those that are less likely to match the cream of the crop candidates, are exposed to the best of the best. Although it may not be realistic for them to match these people, they fill every year regardless, so why not take a swing for the fences and use up most of their interview slots on these top applicants while including just enough lower tier applicants to fill safely? The top percentage of applicants snag more than their share of interviews, a problem that is actually exacerbated by not capping applications.
In addition, this degrades programs ability to choose people who actually want to be there when choosing from the middle of the pack applicants. They have to go by really soft or random things to decide who to invite. Whereas with an application cap, it is very clear that everybody who is applying to your program is seriously considering you. I argue that this would actually increase lower tier applicants chances at the programs they would like to be at, within reason. Maybe you don't get to take as many shots at the moon (which might initially feel more detrimental), but you actually end up with MORE say over where you're likely to match.