It's been widely noted that Arsene Wenger and Sir Alex Ferguson were great at developing young players, but I think that is absolute bullcrap !! In the 27 years SAF was at old Trafford the only kids he developed who turned out to be good players were:
Beckham, Giggs, Sharpe, Butt, G Neville, Scholes ...... I'm struggling to think of any others.
Wenger has even fewer successes in his 19 years at Arsenal:
Cole, Wilshere ..... I literally cannot think of any other player who he developed that was decent !!
Stars in the making, players who would have made it anywhere with any manager are not counted. The likes of Rooney, Ronaldo, Fabregas, Robin Van Persie, Anelka, for example, are not counted. I'm talking about players that came through the youth system from a young age, not pinched from Barcelona's academy.
So I put it to you that neither manager was particularly good at developing players.