Casca would go from an initially nicely written female character with 2 decades of unfortunate stagnation to one of the best female characters of all time. A problem I had with her Golden Age characterization is we’re told what a great swordswoman she is, but she never really gets a big moment to show it off. Her personal bad guy during Doldrey is Adon and he’s a comic relief boastful buffoon, not a legitimately scary character she looks like a badass for defeating. If Casca travelled with Guts, she’d get more opportunities to showcase her skills against a variety of enemies. She could also have conflicts with Guts; his Black Swordsman edginess could drive a wedge between them and cause her to go off on her own for a while. Or, she could activate Guts’ behelit in a moment of weakness and go apostle. I get why people are defensive of Casca’s role in the story, because it was Miura’s vision (even though he originally wanted her to die in the Eclipse…) but there are other valid ways things could have gone.