He has improved both technically and tactically. To be honest, I wasn't sure he'd be able to, because he seemed pretty locked into his own way of playing, and has a huge cult of Yes Men behind him; that's always dangerous for a talented young person. But it's not the first time a talented player has improved after a year+ playing with Barça. Sanchez, for example, became far more adept at short passing. At a lower level, Rakitic is also improving, compared to his first season.
With Neymar, I'd say it's a combination of adapting to the more technical demands of La Liga (you just can't play as sloppy [a.k.a. "open"] as in Brazil) as well as finally understanding it's more effective to use the options his teammates give him (and have been giving him since day one). One can't say if he came to that conclusion on his own, by watching/emulating his teammates or reviewing his own performances, or was guided by Messi, Lucho, Alves, whomever.
Whatever the reason, if he keeps playing this more connective teamplay like the rest of his teammates, he's only going to get better at it, because his skills will have the chance to be refined and developed for those situations. It probably works both ways, self-fulfilling- he didn't take use those opportunities previously, because he lacked (or didn't trust) his abilities to do so, so he failed to develop that part of the game. Now that he's technically improved, he's trusting those opportunities, which means he'll try them more often, and the execution and understanding will get sharper.