Something I've noticed, is that very few people who seem to have concerns over ZZ and whatever issues he had, last year, have acknowledged that he came in late (August?) and that he will likely continue to improve his areas of weakness. If there is one position I have absolute faith in Barnes being able to coach up, it's point guard.
IMO, the issue that will always limit ZZ will be his size because he can't change that. His size isn't going to prevent him from playing PG, though. He can clean up the ballhandling. I am fine with him being the starter. My concern is that I don't want him playing 35 mpg at PG. We need someone else, either to start over him, or to spell him. I'm not particularly keen on the idea of that player being a true freshman. I think a lot of people take for granted that we had two freshman PGs log a lot of minutes, last year, with a lot of success, but that is certainly the exception and not the rule.