I'd expect him to play in an inferior league. There must be a reason no English club were in for him, yet Milan were.
He was always going to do well in Milan. Not one bit surprised. But I'd also say he started well for us in his two spells and then complete disappeared.
If you think that any set of fans know more than Enrique, Emery, Villanova and Koeman (you could even include Nartinez but that's debatable whether he knows more than your average fan) then that's up to you, is suggests there's a reason we are posting on the internet and they're being paid millions to make these decisions.
Apologies for repeating myself, but:
Enrique - loaned him out, then wanted him back
Emery - no real reason to play him given that he was in a winning side
Villanova - gave him his debut (and was actually the only Barcelona manager to pick him)
Koeman - picked Lennon, Valencia and Cleverley instead and persisted with a system that wasn't working for most of the time Geri was here
Martinez - loaned him, had a good first season out of him playing one style, then brought him back and played a different style
Deulofeu needs playing time to develop; its been obvious ever since he first came here. Playing him in bits here and there never works.