I don't know if I would say he has more potential overall...but they are players who can play different roles. Gotze can boss the mid field or you can throw him on the wings. Neymar is a pure forward.
As far as playing to their potential....Gotze imo is more advanced at this time. Neymar could be capable of being one of the best someday. But right now he doesn't impress when given the chance and has failed to shine against top opposition. Gotze meanwhile has cemented his place in the national team and won man titles with Dortmund in a stronger league.
This kid has REALLY been tearing it up this year even after being injured for a bit. He plays with the confidence of a much older player. Is also a tough little bugger.