Re: should batman appear in the MOS sequel?
If there is a need to have him in the film, they should follow Iron Man as an example, and have Bruce Wayne appear in a post credits sequence. That option would allow for a direct connecting thread, and would not compromise the main narrative of the film.
Justice League (TBD)
Batman: Ben Affleck. Superman: Henry Cavill. Wonder Woman: Gal Gadot. Green Lantern: Tom Anderson.Darkseid: Michael Cera.
Aquaman: Alexander Skarsgard. Martian Manhunter: Liam Neeson. The Flash: Neil Patrick Harris.