Honestly, I feel he started with overcomplicating stuff since we kind of lost form. Maybe he will start playing more efficient again once the midfield is back to its level.
When you look at his whole career, Santos, Brasilian NT and Barca, then:
1. he wasn't overcomplicating things ONLY in 2014-15 season
2. in Santos he complicated all the time
In Brasil, he is the master of complications
In Barca, he is a true himself currently.
I have said a few times before, this style of playing is a TRUE Neymar.
When he played faster in 2014-15, he was playing against his natural instincts.
Sadly, he returned to his natural instincts again, to his natural self.
That means, slowing down the game, and trying tricks whenever possible, no matter what.