You could probably add Adama to the list of talented La Masia players we had that had hype.
Dude had the physicality and the technical ability but didn't have the brain to put it together at the time. He appears to be improving in that regard since he left us and I hope he keeps improving.
Deulofeu suffered the same problem, he wasn't physically gifted as Adama was but he had the technical ability but lacked the Brain to put it together. He got binned by Lucho for just being so egotistical in his decision making, it was the same with Valverde as well.
Cuenca I don't think had that talent of being more than just a bench player but was very useful before Injuries Destroyed him and as for Jeffren, seemed useful at one point and scored the Manita but again never really seen him more than just a squad player.
Think Munir can be added to the list as well, looked good during his younger years but like Adama he was apart of that terrible Barca B team that was poorly managed and his development stagnated and went from being a top prospect to just being an average-good talent. Seems like Sevilla and below is his level now and he's not doing to bad over there.