Pereira was the stand out in the underage teams and the feeling at the time was that he was one of the few young players at the club that could have a real future. But he got limited opportunity.
My issue with LVG's approach was exactly as you described. There was no identification of real genuine potential. Just have a lot of kids as back ups who will get a game if some injuries happen. No plan to integrate them into the team. Just let luck decide.
On Tuanzebe, how old was Regan Poole when he made his debut under LVG? As above, LVG had absolutely no plan to integrate the better prospects. Tuanzebe may have been injured when he needed a defender, or maybe Donald Love played better in the previous reserve game.
Whats the problem with that though? Adds further competition for places don't think that's a problem. If a players in form then why not reward them, it gives all our young players hope. If Tuanzebe was injured then that's just plain bad luck on his part. Regan Poole got 1 minute under LvG against Midtjylland in 15/16 having played for Newport on loan the season before (1013mins). He was 17 years old I think.
I'm sure there was a plan in place for our kids but injuries wrecked our senior team and they were called up to fill places. I commend LVG for his youth policy, he didn't move senior players from other positions to fill in as emergency stop gaps, he trusted the youth would do a job. Ultimately he didn't have the quality at the time to be able to rely on that though.
Shaw missed 51 games due to his leg break
Jones missed 32 games due to being Jones (injured)
Valencia missed 29 games due to injury
Rojo missed 27 games due to injury
Young missed 13 games due to injury (he was later used as an emergency fullback this season)
Darmian missed 7 games due to injury
Smalling missed 3 games due to injury
Blind missed 0 games due to injury
We basically had 2 CBs, 1 LB and 1 RB out for over half the season.
Jose has 'solved' this issue by bringing in another senior CB and a promising youth player RB. He also uses Matic and McTominay as emergency CBs. I seem to recall we may have used Carrick in a few games at CB in 15/16.