Excellent post CDu. I have to spread comments around or I'd spork you.
I totally agree with you on RJ's efficiency. I want him to become a more efficient player. That said, RJ is so good at scoring that he's incredibly valuable just for his raw point totals. Bart Torvik has an offensive stat that he modified from other stats called
PORPAGATU! ("Points Over Replacement Per Adjusted Game At That Usage" or "PORP" as it is abbreviated on each team's stat page). You're a big stats guy so you probably understand it even better than I do, but basically it's a way to attempt to place value on a player's production based on usage. For example, Jack White has a higher ORating than RJ Barrett, but no one would argue that Jack is a better offensive player. According to PORP, RJ is worth 5.4 points per game more than a replacement player (this puts RJ in the 99.9th percentile). Jack is worth a strong but probably more accurate 3.4 PORP (which falls in the 94th percentile). To put this number into perspective, RJ has a higher PORP than Austin Rivers, Jabari Parker, Jayson Tatum, Brandon Ingram, and Jahlil Okafor. Even if he's a little inefficient, he still gets buckets that no other players can even attempt.
And while based on O-rating he's had some tough games, in the 8 games he's played against T-Rank's top 50, his PORP (which is adjusted based on the quality of the opponent) actually goes UP to 5.6 (just as a note, Zion's goes up from 6 to 6.8 against top 50 competition, which is just otherworldly good).
Anyway, this isn't to say that I disagree with you in any way. I think it would be fantastic if RJ figured out how to put just as many points on the board while also improving his efficiency. However, PORP helps to highlight just how valuable his raw point totals have been for the team . . . especially against teams with good defenses that might be able to completely neutralize less-talented-but-more-efficient scorers.
That said, clearly Zion needs to get the ball as much as possible because whether you go by O-Rating or PORP!, Zion is in a class of his own.