James Gunn (Guardians of the Galaxy franchise) already brings a bit of Marvel superhero experience with him for Warner Bros. DC Comics' flick The Suicide Squad. The writer-director will be taking another crack at the title team of supervillains and has already filled up the roster with quite a few notable names, both from the comics and Hollywood itself. Now it sounds that Gunn will reteam with frequent collaborator Nathan Fillion (Guardians of the Galaxy, Super, Slither) as well as fellow MCU filmmaker Taika Waititi (Thor: Ragnarok, Thor: Love and Thunder), both of whom are joining the cast. Deadline …