Just finished Samurai Jack after the series concluded and watched the entire series over again. The original series will probably be remembered as one of the Top Ten cartoons of the generation and the final new season probably drops that down to between like 11-20th rank. The best way to put it is that Genndy tries to Gurren Lagaan and Killing Joke the final season all at the same time so you get some incredible build up to a very rushed ending. Still somewhat satisfying but it does undercut a pretty important element to Jack’s legacy by doing something pretty bad.
Season 1 and 2 are near-flawless. Season 3 and 4 have incredible high points and patheos but each have one episode that’s flat-out bad. Jack really should have stayed a serialized story with one GIANT finale rather than a continuous buildup that goes back-and-forth between Jack’s development.