One thing I noticed that has matured a bit is the gem cutters. The original game they had this high-pitched voice that was fairly innocent, but could also come off as sickeningly childish. They changed the voice in reignited, and now it doesn't sound so cutesy. This could arguably be a good or bad thing depending on your opinion of the original gem cutters, but if you hated that immature high-pitched voice of theirs, then it's actually a nice mature change.
I am also anticipating the post magma cone epilogue. Does the Faun still casually murder one of his friends by pushing him into the lava?
Because in the Colossus epilogue, the student still crushes his master without any indication that the master was all right.