Judging from this video this kid is too good for Barca B. I think sometimes he already knew where best to pass the ball and was frustrated that his teammates weren't there. Keeping playing like this isn't good for his development. For a 19-year-old it's the crucial stage. Making one bad decision can hurt your career significantly. (Deulofeu, for example. His weakness has always been in the passing game yet he chose a EPL team. Now he is struggling here despite his great talent.)
I think the question mark over this kid is: can he continue to play like this when he's pressed in a high-intensity La Liga game? If he can manage he can at least be a squad player (like Rafinha). If he plays and delivers he may be a star. Personally I hope he can work more on free kicks and long passes. (Since every great midfielder is quite good at these.)
I think, ideally, he should be competing for playing time in a tiki-taka team in La Liga starting this year. No need to stay in the comfort zone for too long. Hopefully one more year in Barca B turn out not bad for him. Deserves to play Copa games. Absolutely needs to be loaned out or promoted next season.