One of the reasons why superhero movies are so successful and profitable is a majority of them are four-quadrant movies, which appeal to the four major marketing demographics - both male and female audiences, and both over and under 25. Tentpole movies are made for most everyone, so keeping its language, action, and overall content a family-friendly PG-13 is very important to a movie studios bottom line.
Most superhero movies can push the boundaries of the PG-13 rating, so filmmakers can have the creative freedom to tackle mature themes and stories without crossing the line into an explicit and violent R rating. Christopher Nolan's Dark Knight trilogy comes to mind for stretching the idea of a PG-13 movie. The movies featured realistic-ish violence with a mature-ish subject matter, but stayed sanitized without showing blood and gore or sex.
While the DC Expanded Universe is aiming for realism with a darker and grittier tone, Warner Bros. is still trying to make these movies profitable and broader for mature audiences. DC producer Charles Roven revealed to Collider that all the movies in the DCEU will be made with the PG-13 rating in mind (a la Batman V Superman), instead of going for an R rating. He explained:
“Right now the movies that we’re making, the movies that have been announced by Warner Bros., I would say those are all intended to be PG-13 movies. I can’t tell you something may not come out of left field or we might get inspired to develop a different character, but the ones that are in front of us right now through [Justice League 2 are] PG-13."
Roven elaborated with Warner Bros. intentions with making the DCEU PG-13 when he talked about how far director David Ayers pushed Suicide Squad. The supervillain-centric film features many characters who are insanely violent, but when it's released in theaters in August 2016, it will also receive a PG-13 from the MPAA. Roven explained:
“The intention of the film is definitely to be PG-13… We really want to make these films tonally consistent so that, as I said because this is a shared universe, at least our current thinking—and again, we’re not dealing in absolutes because while this is business it’s also a creative endeavor, so you want to leave yourself open to changing your mind, doing something different, being inspired, that’s the whole process of filmmaking is you have to allow for inspiration as well as having a road map for what you’re gonna do. So our plan right now is to make all these films PG-13. In some cases, you know, right there on the edge of PG-13, but still PG-13.”
This makes sense if Warner Bros. wants to make real money with their superhero slate. If a superhero movie is rated R, then it limits the audience draw to people over the age of 17 and that cuts into the very important family aspects of comic book movies. It's not to say all superhero movies should be PG-13. It just really depends on the character.
For example, Fox is releasing Deadpool in February with a hard R rating because the character is extremely violent and foul mouthed, so making a PG-13 version of the character wouldn't stay true to the Merc with a Mouth. It's going to be interesting to see if Deadpool would be as highly successful for Fox like the main X-Men franchise. If it is, perhaps we'll see more and more superhero movies push for more mature content and language.
Batman V Superman: Dawn of Justice opens on March 25, 2016, which is followed by Suicide Squad on August 5, 2016; Wonder Woman on June 23, 2017; Justice League Part One on November 17, 2017; The Flash on March 23, 2018; Aquaman on July 27, 2018; Shazam on April 5, 2019; Justice League Part Two on June 14, 2019; Cyborg on April 3, 2020; and then Green Lantern Corps. on June 19, 2020.