I think part of FFXV's problems is that it's shackled to what Versus XIII was. They can't even change the main designs because of the deal with Roen.
Really?
With FFXV, it feels like there's a struggle to try and appeal to both the west and Japan. You have the future timeskip design for Noctis that looks completely different from his regular design that the game starts with as if to say 'Hey! This guy will look badass at some point!'. Personally, I expect after FFXV likely sells below expectations, for the next game to take more inspiration from Game of Thrones for its designs and story.
Obviously, there's the open-world aspect which is currently what's popular, but it doesn't seem to do anything more than what other rpgs have been doing and actually seems like it may fall into the traps that have been criticized about open world rpgs recently. The biggest draw to me so far has been seeing the monster designs as well as how some of the spells work.