For the record, Mankiewicz isn’t the “probable” replacement, he is the replacement and has been picking up for Osborne for years now.
And I really don’t know much about The Young Turks or why people hate them so much, but the fact of the matter is his involvement in that has nothing to do with his TCM hosting abilities.
A bit more on topic, I’m disappointed that I didn’t get to go to more TCM in theater events when Osborne was still around (or actually make it out to their festival in person). One I did get to see was Singin’ in the Rain, which had an interview attached between Osborne and Debbie Reynolds. It was pretty fun to watch. Sad to see them both gone now.