You only need to watch him to see he loses concentration easily, which is a shame because he has everything else to be a top central defender, but it's a crucial part.
I'm all for giving players more time, but that sort of thing comes naturally.
If we are playing a back four then as I said before, Bonucci would be last choice for me, but I expect Ogbonna will make mistakes. At sweeper Bonucci is easily our best option. He will make mistakes, but anyone there will, and you will see that if Ogbonna ever gets a run there. The position is about responsibility and risk.