I think this is an example of the difference between "hope" and "expectation". People might hope to see Clownpiece, Hecatia et al, but I doubt anyone sincerely expects it to happen.
I'm "expecting" to see some of these characters again, at least once. Since MoF, every game has had
at least one character with multiple appearances. Sanae became a main player character, with her, Suwako, and Kanako all being important to the plot of future games. Nitori, Suwako, Utsuho, Koishi, Unzan, Byakuren, Futo, Miko, Mamizou, and Sukuna all became playable in fighters. Seija got her own game, and a bunch of the characters showed up in the manga.
I don't think anyone's expecting to see them as bosses in a main game, or playble characters, or getting their own spinoff, but I'd be really surprised if these characters
never showed up again.
And besides that, Hina and Medicine were both pretty unimportant to the plot of their games, and unimportant as a whole in the grand scheme of things. Clownpiece is
not really noteable, but Kishin, Junko, and Hecatia certainly are AMERICA.
Edit: fixed