I think he has been pretty great the few minutes he's played. Showed some great dribling and ability to get quickly past players and driving the ball up towards goal, and is usually pretty good at picking out a good pass and deliver it accurately.
Loaning him out might be a good idea, but I seriously think he could be ready for a bigger role in Barca as he is right now. He hasn't really gotten the chance to show how he can perform over a longer period of time, which is the only way to properly judge how a player works in the team. Nerves can make a great player seem poor if he's only getting 20 critical minutes to play and show what he can do every other week...
The only "youngster" that has gotten a proper chance this season is Bartra, and that's because of injuries on other CBs. A shame we don't have a coach that is giving the youth a bigger chance, we seemingly have to loan out everyone first before wanting them back for a spot in the squad.