I guess the obvious question here, is Potter better than Tuchel?
Tuchel is far more proven, especially at that level, but while an obvious question I don't think it matters that much given the context. There aren't many managers available to Chelsea at this point in time who are better than Tuchel, and the timing of the sacking and the murmurings behind the scenes point to problems between Tuchel and Chelsea beyond his capabilities as a football coach.