I'd say Fantastic Four (if the upcoming "Venom War" is indeed the climax of his run and if the FF title is relaunched just in time for the 2025 movie). A way for him to keep working with Tom Brevoort (still the FF editor) outside of the X-titles and because Al Ewing seems a good fit for the FF (a fan of Jack Kirby, Dr. Doom & Galactus, the writer of several cosmic teams and the event Empyre in the past and also Immortal Hulk #49, a peculiar issue which can be described as an ode/love letter to the first family).