Agree that ability is one of Barkley's major strengths and you'll never get it perfect, but there is a time and a place to do it which is I think what Naismith is getting at. Iirc other players have said similar things including Jags and Distin.Even on that narrower issue of taking other opposition players on and losing it, it's wrong to try and censure Barkley. Just looking through the stats for the same period and it shows that he carries the ball forward about 30 times in 5 games and is successful in roughly just over half. That type of play is not a feature of Naismith's game (he barely goes on a run with the ball once in games on average). He's basically asking Barkley to limit his own game in that respect, and it makes no sense. That's the nature of this talent, and you'll never get 100% success doing it - not even Messi will nail the majority of his own forward forays.
I'm not ignoring Naismith's own attributes here. I'm merely underlining the point that limited players have no business using some BS conceit around their own 'experience' to offer a gifted player advice. I'm sure Barkley will cast those words aside. He needs to too. What we dont want is the tethering of his ability to suit some ridiculous critique from a man who should try and put his own house in order.
Imo his words weren't intended to be as critical you are taking them and don't see a problem with any of our players pointing out he isn't the fully developed player yet but each to his own.