I'm not expecting many characters to change, in part because I think this patch might just be cracking down on mods.
However, the only Rosalina changes (my main and I haven't played in a while so memory on other characters is fuzzy) I would want are:
-Fix her grabs, they're still jank
-Give the windbox on Catch & Release more power and maybe some more range (it's a custom move so buffing this does not effect competitive play or For Glory Warriors, don't wanna hear any complainin')
-Some general hitbox clean up, mainly on Rosalina and Lumas rapid jabs
Though to be honest, I kinda gave up on Smash so it doesn't matter much at this point. She could be nerfed like crazy and it wouldn't have much bearing on me (though I'd still think that would be really dumb).
I also think they may wanna do something about that anti-Cloud tech that was discovered recently, but it might just be a fitting slap on the wrist that he needs, and having it means there's no real reason to cry for him to be nerfed.