I already said he is better than he was in years past, point acknowledged previously. The bold is my concern. By PER Boozer is far better than Al Jefferson. By PER Paul is the best player in the NBA this season. The PER is a decent representation of who is performing in multiple areas of the game, but one problem with it, is that it smooths over weaknesses in the players game.
CJ's PER is improving, that is good, obviously it simply supports what has already been acknowledged, that he is better now than he was the past 2 years. But his FG% and 3pt% have both dropped year over year for the past 3 years. His FT shooting is better, that is good, and he is scoring more, but not more efficiently. If we futher break down the PER stat, his rebound, steals and assists are all better, but basically by percentage points (1.0 this year vs. 0.9 from last year in steals I believe, 1.8 assists vs 1.7 last year, but he is just shy of one whole rebound better, all in nearly exactly the same playing time). He has bumped his PER by volume of shots primarily, that is about it. He is taking 2 more shots per game, and making less than one more per game. He is taking not quite one more freethrow per game. PER, like any stat, can be deceiving. The argument could be made (I am not making it, I just wanted to point out that it could be made) that he is not really any better, rather that he has just been given a green light to shoot.
I personally think he is doing better than last year, and the year before for sure. But I can acknowledge his slight improvement while still remaining objective enough to recognize he is not our answer at wing. And if his pace of improvement is any indication, he won't be there any time soon. Extra shots and a lower FG% with very marginal increases in reb, steals, assist, etc. does make for a good formula for development. I don't want a CJ who is hitting 38% from the field on 18 shots per game, even if it does bump his PER to 20.
You are right that what he turns into is wide open, and he could get better, or worse. I just hope he gets there, or we replace him, to help us get to a championship caliber team before Deron leaves. If Deron leaves and one of the reasons is we never plugged the hole at wing that is almost universally recognized as a major weakness, well that will be a heavy price to pay for CJ's development.