I agree with the first para that Rooney was never athletic and lacked the proper discipline. I'm not sure about if Barkley is a model professional, since I have not really watched him play (except when United play Everton). But I do disagree with the notion that Rooney has far greater intelligence and flair. I think Flair wise, Barkley is superior at their respective ages. Barkley can actually dribble past a player. Rooney just Bullies (or used to) them. And rooney has a good awareness of what is going on around him, which helps with his decision making. But what little I've seen of barkley, he seems to have a very keen eye. He tries passes, that only the likes of Ozil or Silva can actually pull off. Rooney doesn't dare to make such passes. His choices are usually conventional or standard. or safe. His vision is fairly limited in that sense. Whether you can box that as "Intelligence" or "Vision", I am really not sure, since these terms are highly subjective. But I would give more brownie points to Barkley for the Flair and Intelligence terminology.
Lets not fall into the trap of seeing Rooney as he is today.
These days he is an utter fecking coward with the ball, so the chances of him displaying any vision are long gone.
He has also been conservative on the ball since about 2007.. once Ronaldo started to hit the big time, Rooney never really attempted the spectacular with any consistency ever since - become more stat focused.
In terms of dribbling past players using sheer technique.. agreed, Rooney has never had it. But he had very imaginative and creative shooting ability.. he could pull off some mouthwatering passes - great crosser of the ball as well as switching the play, his movement off the ball was superior to Barkley.. could operate as a 10 or 9. He was a better matchwinner in general, he had an innate sense of how to grab a game by scruff of the neck and produce the key moment to win it. His play in the final third was just more intricate and penetrative - 25+ goals regularly with just as many assists. Remember that Rooney pass to Tevez in the 2008 ECL final.. that was typical Rooney, inconsistent.. but capable of aggression, sheer magic and making match winning contributions.
His peak in terms of flair was 04-07 - he was capable of magic which at that stage was mindblowing.. there was a reason why he was called the white Pele. He could pull off volleys which were Van Bastenesque.. I have never seen Barkley pull off shots with the same level of difficulty Wayne did during those years, that hat trick against Fenerbache...Barkley wouldn't be able to pull off something so audacious even now. Those FA cup goals v Boro.. sublime technical feats. Wayne was something truly special to behold.
His passing in the final third, his one touch play.. his backheels, they all had purpose, directness.. it was full of flair but very effective. He could combine 'street' with winning in a way someone like Ronaldo was unable to when first breaking through.
Its just a shame he was so deficient in key technical aspects which many were blind too and due to his arrogance and possibly poor management, he never really took his game to another level aside from becoming a better header of the ball.
Barkley on the other hand is someone who loves to work on his game, he might start off slow compared to a Rooney .. but he is someone who is at the fulcrum of each game he plays, he is more consistent in all technical aspects and has more control to his game. He is someone who can mature into a proper big match player and actually live up to the hype.. not just show flashes of magic and go completely missing in games.
He has to improve his decision making, be more direct and be more elusive in terms of his movement. He needs to learn the art of winning games as well.. he can dictate the flow of the game but it isn't subtle enough.. he is abit too in your face and easy to defend against. He needs to become a more clever footballer. Wayne was naturally more clever and his game more mature.
You get the feeling with Barkley that rather like Nani.. he is someone that is so gifted, so full of ideas that he sometimes overthinks it and doesn't pick the simplest solution which is often the most effective. Most young footballers struggle with this but in the last generation we had Rooney and Messi.. both of whom had that intuitive football brain which usually picked the best option when close to goal. I think he can develop into a better passer than Wayne but it isn't a certainty.. right now Wayne at his age was a more better final ball passer.