Potter was superb at Brighton but he came to Chelsea and became ass.
Potter is a good coach, no doubt about that, but he is also an average coach and the success that Brighton recorded while he was still there was not just because he was a good coach, it was also because the players in the club a very good and technically sound that is why even after he left them they did not start losing games but currently in the Premier League I still in a very good position. Chelsea needs an experienced coach that is not average.