I don't really think that the Kawhi comparison is apt (Barnes is barely better from 2 than Kawhi was despite being much larger than Kawhi was/is, and Kawhi shot about 20% better from the line which was encouraging for predictions of his shot long term) but I do agree that Barnes needs to go somewhere that can maximise his strengths and minimise his weaknesses while simultaneously improving those weaknesses over time.
My concern is that we aren't that team. Barnes' best skill on offense, by a country mile, is his passing and I feel like unless his shooting improves drastically, by at least 10% from 3 for example immediately, he would essentially be the Big Version of rookie Lonzo. Which is a player which can have some value via connective passing and defense, but need I remind anyone how atrocious Lonzo was on offense before he could shoot? Hell, he can shoot now and he's still not great.
If the Pels draft Barnes they're essentially betting that they can do the magic shooting improvement on yet another guy, and in this case potentially starting from the worst beginning point of anyone they've done it to thus far. Maybe they can but that's a huge bet when you're making a top 10 pick and Franz Wagner is right there.