Pogba, Cleverley and Hazard would be horribly unbalanced. Not a defensive clue between them.
I see Pogba being moulded into the box to box midfielder a la Vierra / Roy Keane as his eventual position and so provide protection for the defence. Cleverley plays a classic CM role and Hazard given license to roam into attacking positions.
All three are still young players and can still be moulded into positions that a club requires of them. Thats certainly true for Pogba and Cleverley.
Maybe Hazard has evolved into his most effective position already and even then, its a number of positions he can play, as the attacking member of a midfield trio, as a classic no 10 or even wide right. He is very versatile as is Cleverley.
Pogba, we still don't know the flexibilities he has. If he stays (and its looking likely he will) , he can be moulded into the player we need him to become.
My mind drifts back to Michael Carrick who used to play in a very different role at Spurs before we singed him but he has eventually become one of the best defensive midfield players in the game. Even at the ripe age of 30, Giggs was able to adjust to new positions .... I could go on.
If we sign players who are "United players', who have the deep desire and temperament to wear our shirt, and who value the teams success over their own, then anything is possible.
I think you are being overly judgemental on these 3 players given their current playing styles. Im personally very confident that if we can get all 3 committed to the club, heart mind and soul, then over a short period of time the University of Carrington can evolve them into a perfect 3some (adding Martinez to the mix would be amazing!).
They would have an experienced Carrick, and I hope he recovers, Fletcher, as well as the bozzo that is Anderson, if he still around, to learn from and give them breathing space to develop as a unit.
Of course I pray that Paul Scholes and Ryan Giggs will by then be 1st team coaches and so pass on all their wisdom and know how to them all.
What more could any young footballer with God given talent want?!