Deadpool is actually owned by Fox, not Disney. X-Men & Fantastic 4 are 20th Century Fox, Spider-Man is 50/50 Sony & Disney, and the rest are Disney's Marvel Studios (the main branch). But Disney has made plenty of R-rated films, which is perfectly fine, and more of a reason why Disney should buy 20th Century Fox.
Disney has already made plenty of r-rated films like Ruthless People & Good Morning Vietnam. Personally, I think Disney should release R-rated movies under their name as the MPAA is a stupid company that stifles creativity.
Disney should instead focus on canon Disney. Does Good Morning Vietnam fit the 'Disney name'? Not really, as with plenty of Touchstone PG films, but Alien, for instance, could actually work under the Disney name. And of course, Deadpool, once Disney owns it, would be great for Disney to market as Marvel, but I don't know if they'll bring that into the MCU.
The 6th Sense is another tremendous non-Disney canon... Disney-made film, so I wonder if having those types of films under the same name as, let's say, FOX would be a good idea, or something new. No need to have different studios when one larger studio or less separate studio could work better, but let's wait and see.