"You don't want to mess with that terrific formula that Fox developed, particularly going with the R-rating, the edgier side of the Marvel universe," Dergarabedian said.
"Deadpool 2" arrives next year, and the studio has been developing spin-offs of its R-rated movies. Disney CEO Bob Iger this week reassured reporters that Deadpool movies, which are only loosely-connected to the main X-men series, would remain R-rated after a buyout.
Still, it seems highly unlikely that Disney would not introduce the X-Men — and Wolverine, the team's most popular character — into their shared universe, which would probably force the franchise to conform to the PG-13 mold.
It's a question of letting fans have their cake and eat it too. While comic readers have waited a long time to see hard-edged heroes in R-rated movies, they have also clamored for Fox-controlled characters like Wolverine and the Human Torch to appear on screen alongside Marvel Studios' Captain America and Hulk.
"They just want to see their favorite characters interact with their other favorite characters. It's what they've been waiting for for a decade," said Alisha Grauso, editor-at-large at Movie Pilot, an online magazine that focuses on genre entertainment.