I do kinda wonder what happened to the premise of the villain system, though. It just kinda stopped being a thing at some point, but without a good reason that I can remember.
I'm pretty sure that the Villain System is implied to be the Curse and the time traveling and fighting Olivia lead to Elsa yoinking the curse from Yvonne and suppressing/purifying it, so she doesn't have that anymore, right? Also, Future Witch Elsa had been actively messing with the system to disrupt/destroy it.
I think that the Witchy Future Elsa may have gone through that door. She talked about the succubus blood love potion giving Yvonne "a health bar" and said she was "exploiting a bug," and later called Yvonne a "villainess," which is all very modern game terms. She also implied she was subject to "punishment" like Yvonne if she told her too much. I think it would be interesting if she performed a full loop like entering the real world and returning to the game just to help Evie back out.