The point guard's job, and what Steve Nash does so well, and Stockton before him as well as all the others who are great at the PnR, is that he uses the screen but also continues penetration to the foul line (extended). Getting further below the foul line is great as it draws defenders so easy baskets are created.
See how Nash gets at least to the foul line extended. That gives him the proper angle, ability to draw help, and a short distance to make a hard bounce pass that's easily caught going to the basket. The screens are set very high towards the top of the key, but Nash uses the screen and gets deeper towards the basket.
Here, Felton gets the pass to Amar'e but it's too far to consistently get positive results. To me, Felton needs to do a better job of getting into the paint, or at least the foul line, consistently, so he can make the defense react more.
Or maybe they should run more 2-man side pick and rolls so that they start near the foul line. Nash aside, Deron Williams is simply the best at it. I guess we can all collectively pray that he decides to dart East to the Big Apple at some point.
It's an essential play to this system and it takes time to perfect. And because you can run so many things off of it, it should be very difficult to stop in the half court. But if you're not surrounded by capable shooters, it makes it that much harder to make efficient.