The franchise is inspired by tons of mythologies, from many regions. But my point is rather, why is someone like Pan or Baba Yaga suddenly a rather notable side-character? None of the previous games have done anything like that. Mythological creatures were just enemies, never actual characters.
The structure of LoS' plot was very different than what came before it. The Castle being just a location instead of the prime one, the influx of Tolkien-esque generic goblins and trolls, the big role for existing mythology (Pan, Baba Yaga, Laura and the Knight, someone else at the end), etc. All these things struck me as odd.
The game just has so much not-Castlevania. Some namedrops to franchise characters can't change that fact.