The Man in the High Castle went from being a high-concept show about an America under Nazi rule to being a higher-concept show about alternate worlds and how Nazis would want to put every America under Nazi rule. But despite its mostly successful marriage of thrilling espionage and science-fiction, High Castle has always been at its best when miring itself in the tricky moral soil that a Greater American Reich would be built on. Luckily, Season 4 does deliver some great character work that makes the most of the past three seasons’ horror. Unfortunately, those moments punctuate an otherwise troubled story, full of too many characters to service and a weakened confidence in its own central conceit.
Source: IGN.com The Man in the High Castle: Season 4 Review