Rafa doesn't need a new coach, he needs a sports psychologist. He just can't beat Nole, not because his game is too bad, I mean.. he beats EVERYONE else with his game, so it can't be that.. it's a mental block in his head, he needs to be confident again.
He does not have a mental block. Mental giants like Nadal don't get those. It is obvious to anyone who watched a tennis match this year than Djokovic brought his game to Partheon levels. Nadal knows that and now will bring his game to that level next year and de-throne Nole.