I am not anti AVB and agree ( when he gate it right ) he seems the real deal. Read my threads and I have whole hearterly supported him. But! ...As a manager who has never played top flight football, this has to effect players in accepting him in the dressing room when he's motivating them?
Honestly I think not. How many players knew what a good (or not?) player their manager was back in the day?
Very few Id Imagine.
Do you think Januzai is sitting in training at Utd looking at Moyes thinking "I remember you, what a player! Im going to try extra hard today!". Has it held Mourinho back? Converseley, did it help the likes of Hoddle (often accused of terrible man management for showing off as the best player there...)?
I think players respect someone who clearly knows what they are doing and gets them engaged in the job. Makes training fun, supports them... and most importantly makes a winning team (a bit chicken and egg I realise).
Do that and your history wont matter at all. AVB has spent years working within the game, Mourinho had him on his staff - Im sure no mugs make it that far - and has now spent a few years learning to manage. From recent history he is also a winner, of a treble, which while "it was only Porto" the players WILL know of and recognise.
He obviously has much to learn still, but Id say he is where he is on merit and the players have no issue with his background.