Creative Screenwriting brings us the following from an interview with Mark Bomback (co-writer):
MCKITTRICK: Where(sic) there characters or concepts you wanted to use but were unable to, whether because of studio decree or because they just didn’t work in the story?
BOMBACK: I love Rogue and I just think that there’s something about this idea that Rogue is tremendously empathetic but incapable of safe human contact. That always moved me and I thought that’s what really got to the heart of what makes the X-Men franchise so unique. So I was trying to do something with Rogue in the script. I even had a set of ideas that the old man possessed a version of Rogue’s power and that was going to be indicated by a white stripe in his hair. Eventually it became very goofy, and I threw it out because I started realizing throughout the script that it became more problematic than cool. It’s no accident to me that in the first X-Men film the first two mutants that you really see who have a connection are Wolverine and Rogue. There’s something special between them, so I was trying to bring Rogue into it, but it just didn’t get there. I regretted there wasn’t a way to figure it out, but when I look at the film now, it would have stuck out if we tried to shoehorn her in there just because it was another character from the universe.