Maybe I'm overlooking something on the film side of things but looking at the top movies/franchises Fox has I'm not seeing a lot of heavy hitters. Aside from gaining full rights over Star Wars and folding the X-Men and Fantastic 4 back into Marvel (both valuable but unnecessary) I don't see much.
Avatar? Yeah it made a ton of money and Disney has invested a lot in Pandora but there's a long way to break even on that. Other than that, Star Wars, and Marvel the top movies of all time out of Fox are Independence Day (22 years ago), Home Alone (27 years ago), and Night at the Museum (11 years ago).
For franchises it's Planet of the Apes, Ice Age, Alvin and the Chipmunks, How to Train Your Dragon, and Die Hard. Most of them seem played out, except maybe Planet of the Apes?