Well, the criteria was recognizability, Malificient is somewhat familiar, Madame Mim is not.
Mostly because Malificient keeps appearing in Disney games a lot, usually Kingdom Hearts as a supporting villianous character, often undermining the Heartless Council to further her own goals.
I’m guessing Disney have a vested interest in Malificient, given she appears in not only the abovementioned games, Once Upon a Time, Descendents (before ending up rather ingloriously as a newt) and her own spinoff movie.