PATTERNS OF FORCE was described by someone at the IMDB as "the serious version of A PIECE OF THE ACTION". That's about right. Unlike the alleged "parallel evolution" of THE OMEGA GLORY and BREAD AND CIRCUSES, the gangster planet and Nazi planet were both the direct results of Earth missions contaminating the indiginous cultures. Of course, this meant in both cases, Kirk was free to "interfere", since he was trying to put right was was put wrong from previous interference.
This was one intense, nasty episode... and yet, unlike B&C, it's eminently watchable, even entertaining. I wonder, maybe Nazi stories are easier to deal with than Roman Empire stories, because in WW2, there were, in the long run, much greater powers poised to take down an obviously insane, hate-filled, self-destructive country... while, with Rome, there was nothing to stop them (apart from a mesage of peace and brotherhood, which itself became perverted when a Roman emperor decided to CO-OPT it as his new STATE RELIGION).