I mean even putting in the 1 season rule is pretty shady, I got an idea from dota 2 in-house groups, they have already approved players vouch for players and that is how people get in. Maybe we could count a season of open as 1 vouch and then an existing coach could vouch for them... If we ask nicely enigma might put a section of the forums dedicated to approving coaches, similar to the stream list.
the problem here is that some people would just let friends in, getting a few people that are in close contact with the community could probably approve and disapprove coaches. Though the judges should be kept anonymous so they don't offend anybody.