Before X-23 there was a young mutant named Marrow. Marrow wasn’t pretty, in fact she was a Morlock before joining the X-Men. She had bones which grew out of her skin, providing her with armor and weapons. (Not bad considering her mutant team-mate Maggott had it way worse. Read this if you don’t believe me.) Her healing factor is similar to Wolverine’s, along with her attitude. She had potential as one of the X-Men. So whatever happened to her?
My thinking is that she was ahead of her time. Maybe readers weren’t ready for her “in your face”/”up yours” approach to danger. Or they felt she was too similar to Wolverine and weren’t ready for his female equivalent. In X-Men #72 she and Wolverine butted heads and as you can see, it didn’t go so well for the veteran X-Man.
Everyone loves a bad girl but I guess nobody loves an ugly bad girl. In Uncanny X-Men #346 Marrow’s looks went from butch to feminine. She lost her edge and her personality softened. She became…*gasp* lame.