I liked her as a guest host.
Dr. Bialik would bring some major intellectual creds to the gig.
According to this: “However, in a July 2018 interview with TMZ founder Harvey Levin for his show OBJECTified, Trebek named several potential replacements. He first suggested Alex Faust, the play-by-play announcer for the Los Angeles Kings, or Turner Classic Movies host Ben Mankiewicz. But, when asked to suggest a female replacement, Trebek named CNN legal analyst Laura Coates.”
Some people are angry that Coates was not given an opportunity to guest host, and I would love to have seen her given a chance.
Unfortunately, Trebek never got to see Mayim as a guest host, so perhaps he might have included her in his choices if he had.