It depends on what qualities you are judging this movie. John Wayne as Timojin, AKA Genghis Khan is a stretch. The acting and script may not be the best, but the action scenes, as I recall them from 30+ years ago were a lot of fun. I only saw the movie once.
I watched the trailer and the cavalry charges and other fighting scenes are cool. The clip with the dancers wasn’t bad either. Of course, my judgement is as a 1950’s action movie. There is action and adventure and challenges to the hero. There is also a love interest.
I don’t think this is the worst movie I have ever seen. I think it is one that I will track down and watch again. It fits a lot of the stereotypes of the fantasy adventure genre of RPG’s. If you play D&D or a similar FRPG, this movie should be a fun little diversion.