Honestly is not her appearance, because the comic was performing well, heck once she got the new look she became relevant and was selling well again. Things started going downhill ever since Civil War II which assassinated her character. Then she never got to be fun again, I dont know if Marvel hates the character guts, but her latest stories just paint her on a negative light, and they have made her into a rip off of superman, except without being fun.

Let me give you an example, in one of her recent storylines we have to deal with the fact Carol had an abusive father, dysfunctional family and of course family drama. That is why I mean her stories try to be overly serious now. And bonus points for ruining Carol's entire family as up to this point they have been shown on a positive light and this family issues came out of nowhere. Character needs cool adventures not drama