A small thing I'd like to see more of is the various X-Men speaking other languages. We got a healthy dose of that in First Class with Erik, and those were some of the coolest scenes in the franchise. And it was rad seeing Storm speak Arabic. With a cast of characters from all over the world, it seems like a no-brainer.
It bugged me in Logan that Logan doesn't speak Spanish, even for a guy as old and well-traveled as him. Made him seem like kind of a hick. Wolverine is no hick. I recently rewatched the scene in Origins where he meets Gambit, and realized Logan should've greeted him in French. He's over 100 pre-memory loss and Canadian, Gambit's Cajun, and they're in New Orleans. Have Remy comment on Logan's accent. It wouldn't have saved that s***show of a film of course, but it would've added a little something.