Created for marketing reasons only?
Even though the original "legends" weren't really true, this is certainly the case today, where you have replacement characters of different skin color/gender/sexual orientation shoehorned into the roles originally starring whites/heterosexuals/males. The new "diverse" characters are, in their own way, conceived more for marketing reasons than as their own agencies, and come with no talented writing, another reason why they're not winning over any of the crowds they think are interested.
And the irony about Bishop is that he was, in a way, still created for a marketing reasons: characters like him and Gambit, as I've figured, were created more for the TV cartoon makers to use as an idea laboratory than they were as protagonists back in the pamphlets. But in the end, what good did it do them? If the original template wasn't conceived well, then it's only bound to taint the adaptations to other mediums later on.