He may be right in general about Pogba's current attitude to the game as I think if he want to be truly great he need to develop a less jovial and more stoic/business-like attitude. If he does I'd expect to see a little less fun and a bit more self-discipline from him within the next two seasons as that's what he needs IMHO to be the best CM in the world.
He already has just about everything in his game required to be the best CM in the world except temperament, Crooks may actual be on to something for once in overall terms of maturity although the haircut is just a symptom of an attitude that I think will need to change for him to be truly great.