It's obvious one of the defensive schemes teams have figured out against the Suns is to chase weakside shooters off the 3-point line. I can't count how many times I've seen Raja Bell pose for a shot, then dribble around a scrambling defender to hit a 20-footer this year. It's something we haven't seen much of until this year. Teams were willing to let the Suns shoot behind the line and take their chances with the percentages, but they've figured out you can't have that many 3-for-2 exchanges with the Suns. The Suns shoot well enough to beat the odds shooting so many threes behind the line.
By chasing the shooters off the line, it becomes a long 2-point shot, and the risk/reward is not really in the Suns favor ... but it's something a guy like JR's going to have to learn if he's going to be a regular rotation player. He'll always get 2 or 3 open looks from the corner just because Nash is on the team, but he has to find other ways to score against teams that are better prepared for this offense. You have to learn how to score out of your own rhythm. That's just the NBA.