Some art will probably be replaced too. I remember Charon in the original hades had his generic robed character portrait replaced with a better one. Zagreus even complimented him on his new look when it was added to the game, which was a nice touch.
Yes, it’s unfinished, but my experience with the original Hades is that Supergiant knows how to make sure their product is at a certain level of polish before making EA available. I haven’t played much, but they seemed to hit the mark again.