My current understanding is that when candidates go to seminary, they're carefully observed in and out of the classroom for qualities like emotional maturity, openness, and honesty. Faculties periodically evaluate candidates for suitability beyond their academic performance. The seminary rector reports to the bishop and the vocation director on the results of these evaluations. Beyond that, the impression I have is that even in seminaries that are alleged to be part of the "lavender mafia" (like the Archdiocese of Los Angeles's St John's Seminary), the day-to-day product is solid priests. The outstanding middle-aged priests at our parish were formed during Cardinal Mahony's time in the archdiocese, for instance.
Contrast this with the accounts I've heard from TEC priests of faculty scandals in the Episcopalian seminaries. Main line Protestant seminaries by and large won't have problems ordaining women or gays, when Catholic policy that I've cited recently continues to say that same-sex attraction is a disorder that can affect the maturity of a candidate, as well as his ability to relate to all parishioners equally. So based on policy, however imperfectly it may be applied (as all policies are imperfectly applied), Catholic candidates are evaluated and screened out if necessary based on same-sex attraction. This occurs as a matter of policy only in Catholic seminaries.
Beyond that, Bp Barron in a recent YouTube video mentions "dry run" practice confessions in seminary. Since no other denomination places the Catholic emphasis on confession as a sacrament (it's in desuetude among Anglicans), no other denomination's seminaries will provide this type of training, nor will they stress the implications in moral theology that are connected with the sacrament. Thus a Protestant priest who's come to the ordinariates after Protestant seminary formation won't have this training. The visitor who insisted there's no difference between Protestant and Catholic curricula didn't mention this, and seems to have minimized its importance. I can't understand why.
So far, I can't escape the impression that the priests who've been removed, laicized, or just treated as problems in the OCSP simply wouldn't have made it through a Catholic formation program. Allowing married priests is a lowering of normal standards that in fact conceals a much more serious deficiency in screening and formation, and the prevalence of scandal and problem priests in the OCSP isn't going to go away.
Yet once more, I wouldn't go anywhere near an OCSP parish. Prudence is a cardinal virtue.