To answer your questions:
1) Yes, Synergy does help players play more like their real life counterparts. It's not as good as in 2K, however. Sometimes you'll see guys like DeAndre Jordan take fadeaways in the post, for instance. And very rarely will you see guys like LeBron or Harden bring the ball up the court. But it's not a gamebreaker for me.
2) Yes, 3 point percentages are still ridiculously high. The elite shooters - Curry, Irving, Harden, etc. - literally won't miss if they are wide open. I was playing around with this the other day, and if I backed off Curry just a little bit, he would shoot a 3 every time and was 8-8 in the 1st quarter.
3) There isn't enough contact in the paint on drives to the basket. However, I love the "physicality" of the post game. You want to back a guy like Howard or Hibbert down? Good luck. I think Live does this really well. The foul sliders when turned up to 100 do work. I've seen many shooting fouls on jumpers too, which is nice.
4) There are still late game AI issues. I haven't seen them as much as others have, but they are there.
Live really isn't that far off from being a very good basketball game. I keep going back to it despite its flaws, but it's hard to get really into it unless they address several of their issues. It would be nice to hear what they are planning on patching.