I'm now 20-0 in All-Pro Basketball. I should have this finished in the next few days. Now that I've reacquainted myself specifically, I thought I'd share some tips for @Khromak or anyone else who would care to tackle this in future years:
If you block an opponent's dunk, hold down the D-pad diagonally in the opposite direction for your best rebounding odds. E.g.: If you are blocking from the left, you'll be holding down + right.
The best accuracy for layups seems to be on the left side of the hoop. Dunks are still the most reliable way to score, but I get through the games faster by shooting from the floor.
If a defender is on top of you deep in your own end, try a half-court shot to get the ball out of there before it's stolen. The ball clears into CPU court about 90% of the time, and I have 50%+ odds of having a player in position to make the rebound and get an easy shot in the paint.
The best bet for stealing the ball is to just stand on top of the CPU player holding the ball; there's no need to push buttons. CPU has a bad habit of sometimes just running side to side near half-court. That's a prime spot to steal. You can also sometimes steal by standing in their passing lane, but you're better off standing on top of the ball-holder unless you're specifically anticipating a pass.
Passing is for suckers. It's almost always safer to run all the way up the court with one player. Just try to run away from the nearest defender at a diagonal angle to reduce their odds of stealing. I will only pass if 1) a defender is on top of me and 2) I have a player selected right in front of me who is open.
You can't run out of bounds or across the back court, so don't worry about overcompensating on the D-pad when you're running away from a defender.