It isn't going to medieval, it is going to be a Mythic Sci-Fi Action Adventure Open World Social First Person Shooter (with third person implemented at certain times). Medieval relates to the Middle Ages or something old fashioned and primitive (the Bronze Age would be the latest). Destiny is in no way Medieval, you are probably just getting it mixed up with (mythic) Fantasy style games. It does draw from the time period in some ways (all aesthetic or governmental so far) but that doesn't make it Medieval.