Blocking shots is really tough. You just have to time it perfect or take advantage of a player who is on a longer shooting animation. Even using Ibaka, Brow, Dieng and other good shot blockers, I'm never able to meet guys at the summit and reject them. I'm really considering bumping the block slider up at this point.
In general, the CPU (on All-Star sim for me) makes a lot of contested shots. They've been shooting over 50 percent against me. Take away some of those contested looks and it'd be more realistic.
I do have a lot of success sliding with left trigger and utilizing right trigger at times. You have to anticipate the drive and then be ready to use the right stick to contest. I've been in tight position and then used triangle to block and been called for shooting fouls (once again, so tough to block shots).
I control off the ball a lot because my CPU teammates are always getting out of position. I believe it's because the 4-5 guys are always picking up their man around the 3-point line instead of just being in position near the paint waiting for them to come to them. It gets them so they're scrambling and that always means they'll get lost. Other than that they will switch at odd times. Be mindful for who is helping from where off the ball. There seems to be much more weakside defenders sliding into the paint but the issue is, sometimes it'll be a 2-3 leaving an open 3-point shooter (even if a 4-5 is in a spot where it should be them sliding over.
Playing D for me is just trying to switch around from defender to defender to slide guys to the right spot. It makes it real tough and can be frustrating if you do everything right only to have a CPU guy hit contested 12-footer that seems predetermined to go in.
I've lost a few games because of this, but only with teams I'm not used to playing with. I usually play with OKC and know them so well offensively, I can always outscore someone with them.