I would like:

The goaltending rule to mirror the NCAA-M rule
The ability to put a "coaching box warning", "bench warning", or "coach warning" in the book, for whatever that's worth
Addition of a direct technical foul with no free throws that counts toward an ejection
The NCAA-M "automatic" hand check fouls, not just RSBQ

Mechanics changes:
Lead able to administer sideline throw-in below the FTLE
Lead's area includes primary on 3-point shooter in their corner à la NCAA-W
NCAA-M switching (not popular)
Ability to use game clock for 10 second backcourt count
Emphasis that C cannot initiate a rotation
Emphasis that the "Official Signals" are more like guidelines

These are just off the top of my head, I'm sure I can think of more.