There was a great parity of points in the paint between the CPU and me in all matches, except some of them in which I purposedly charged the perimeter plays. Like it or not, you will concede about +40-50% of the points this way, but that's also what it happens in reality. If you allow more than 50% of points in the paint, then you're doing something wrong or something is not working properly. See the next points for this.
1) The main goal of deffense is to force them into bad shots. This implies containing the dribblers (more on this later), mantaining composure of the team (don't rush like a mad towards the shooter, this will leave gaps and they can dribble easily anyway, don't abuse of doulbe team) and turning shots into bad shots by using L2 (close pressure). Simply hold L2 and move the analog towards the shooter to lessen their shots if you are nearby. Great defenders in the game really make this effective.
L2 is also a good way to defend post plays, moving analog towards the body of the attacker. Use triangle (jump/block) only when you're quite sure you have decent chances of blocking. And use square (steal) just while they're starting the jump and you're facing them as a last resort to foul them. You risk suffering "and ones" if the shooter is a good and strong one (kobe, lebron...).
Don't run. R2 in deffense should be used only as a last resort or to recover a position or chasing someone in a fastbreak. In other circumstances, It will make you very vulnerable to dribblers.
2) Second goal of deffense is to protect the rim. At long term is more desirable to be crushed with threes than with easy shots in the paint.
When a shot is about to be made, just hold L2 and press X to grab the ball. L2 is the most important button in deffense.
Now imagine this scenario: an opponent dribbler has beaten his man and is about to shoot/drive in. Or a pass is made and an opponent is completely alone and ready to shoot. If you try to run towards the shooter, or move blindly your left analog towards him, there's the chance your players try to fill the hole by going out to help. And many many times this is a mistake because you can't avoid the shot (shots happen) and what you're doing is trying to reduce a menace by creating another one behind your rim, as usually is the tall players that go out. This happens in real life all the time, so this WILL happen to you now and then.
If the CPU has a good position, there's little chance you can influence his shot, so sometimes it's better to just move TOWARDS YOUR RIM and hold L2, so your players, instead of rushing out towards the shooter, try to protect the rebound. Sometimes this works just fine and considering that this year the CPU WILL MISS SOME OPEN SHOTS (which hardly did in past iterations) it can pay off at long term.
That said, I think that offensive rebounding is the main problem of the game out of the box. But last year I thought the same for months until I understood how to protect the rim, and a little slider tweak finally helped fixing it. Using this techniques WON'T completely solve the problem, there's a tendency in the game by which the ball tends to end in the hands of the same player that shot/was blocked and I hope they can patch it. But using all the above, you reduce it a lot. In my matches, CPU has an average of 50% more offensive rebounds than me. Considering I have Gibson, Noah and Gasol, I'm not happy with that. But a week ago it was a 100% more offensive rebounds
As Sauce says, sometimes the CPU gets into god mode and even perfectly contested shots go in one after another. But in my experience this happens only in short runs. Only once I felt it was terribly unfair (when I lost against the Clippers, Matt Barnes and Farmar were hitting shots as if I wasn't there for the whole 4th quarter, but I was bweing raped by Chris Paul mainly which is ok).
