There is a big leap in turn radii between Cat B and Cat C aircraft - some, like the Metro and B1900, seem to fall between two stools. PANS OPS is being amended to reflect that operators must specify under which approach category they want particular aircraft types to be flown, and stick with it.
PANS OPS was developed from TERPS. In the intervening years, the two sets of criteria remain similar, with three main exceptions:
a. the missed approach
b. just about anything involving a turn
c. circling areas
c. is probably the most contentious, and the one area where US procedure specialists would agree TERPS is drastically inadequate.
The radii are far too small, and were probably one of the causal factors of the crash at Inchon a few years ago