@Jamrock, The youngsters of course. You think that they aren't developing? The players at that age can develop even by playing competitive games.
@jklz, On the contrary they do try to play a possession oriented game. However, when the best player on the team is a winger (i.e. Deulofeu) then the coach will focus the development of the game on him. So, with different players, I think it is too much to ask them to play exactly the Barca tactic. Finally, Barca B is a team with (how many?) 5 or 6 new players every year, it takes much time for a new player, coming not from our youth teams, to adapt.