Oh! I had another thought regarding a cool villain they could try for Rogue, that's sorta tailor-made for her.
So the Carol persona... I'm surprised more of the "ghosts" that Rogue has in her head haven't gone rogue more often. I guess it's a good sign that she is a good mental health space and has better control of her powers.
But if you are a writer that wants to give Rogue a personal challenge, that is ripe ground.
It's the classic, "losing control of your own bodily autonomy" and "evil twin" trope wrapped up in one. It's also really popular, with stories like
Doc Ock possessing Spider-Man and
Buffy and Faith switching bodies in
Buffy the Vampire Slayer.
They could set it up as a villain Rogue absorbed intentionally let themselves get absorbed, then have the personality slowly take over Rogue's own body with Rogue forgetting hours or even days of her own memory. Or the personality could grow from within her own mind, as multiple villainous personalities assimilate to become their own 'being'. It honestly sounds like a really fun story to write, so have at it Marvel. (in the unlikely event anyone from there reads this lol)