I agree with most of this... Like Shalacc, I've had success with below average but not awful defensive catchers that can really hit. Typically arms in the 65-75 range and PC in the 60s.
A couple of minor differences, nothing to write home about:
1) I play my very old major league players in spring training a little bit; somewhere some developer once said that might slow decline. Not sure I believe it, but it's what I do. ML players in their prime should not play in ST for sure.
2) I'm even more extreme on training than mmustain; I never play with training less than $20M. It reduces injury frequency, and it's the only rating that helps development of range, arm strength, power, durability, and stamina.