Johnson could not play another game and he will still go in the top 20 IMO. His stats are sort of irrelevant when it comes to his draft stock, he has the physical tools that can't be taught, and only a small number of basketball players have. The sequence when he came out of nowhere for a block against Pitt, and then went coast to coast for a dunk tells you all you need to know, the guy is a freak physically.
The NBA isn't drafting a 18/19 year old kid with the thought that this kid must come in and be ready immediately. 3-4 years down the road when it's time to decide on that next contract is what they are thinking about, and it's obvious that Johnson in 3-4 years will be a much more polished basketball player. He's huge, and he moves like a guard, just seems like he needs some more time to get used to his body and obviously work on the jumpshot.
Hurt is gonna leave, we will see how he fares, shooting is super important in today's NBA, but I think he has a long overseas career and makes tons of money doing it.