I agree with Yaah in that the idea that very few PGY4s feel like they'd be confident in practice is concerning. It could indicate multiple things: it could mean training is inadequate, it could mean pathology residents have more measured personalities and are very risk-averse, a combination of both, or something I'm not considering.
Personally I believe that only two years of AP is woefully inadequate. The training paradigm is far behind the times, back when AP was only autopsies and margins. With the explosion of neoplastic pathology knowledge, and the concomitant expansion of molecular mechanisms of disease, two years leaves little time to learn these concepts in practical ways.
The high number of fellowship candidates, the vast majority of whom expand their AP knowledge either through a "surg path" fellowship or a focused organ-based fellowship, may indicate that only two years of AP is not sufficient to practice modern pathology.
Some programs are certainly better than others. Ownership of one's career requires opportunities to learn. If one is attending a program where scut is valued above learning, such as Albany, Buffalo etc, or a program that has insufficient volume, variety or complexity, then there is a limit to what self-directed learning can accomplish. Also keep in mind that only 50% of pathology residents have US degrees. The other half are FMGs, and many of them are recruited to bad programs, feel strongarmed into being servile and quiet and to not draw attention to themselves, and thus do not bother their attendings to learn more (perhaps knowing that they can't, due to the limitations I listed above).
I called the ACGME about this last year upon the opening of a residency program in Florida in a hospital that had no neoplastic pathology and a volume consisting primarily of placenta specimens and autopsies. What I discovered is that, although the ACGME has an idea of what constitutes appropriate clinical residency training, and can hold programs to task on that, they are unaware of what constitutes adequate pathology training and thus leave it up to the program directors to decide. Things like specimen volume, variety and complexity, availability of ancillary resources or specialized expertise etc are not measured.
As for the high number of PGY1 RISE takers, are there any residents from other countries like Canada, Mexico or the UK that use RISE?