I'm not convinced that Christians just want to see more Christians on TV. Rather, they want to see Christians portrayed on TV in a positive light. Modern TV shows (like Breaking Bad) are about exploring the moral assumptions we make about ourselves, and are often skeptical of objective morality. If a major Christian character were included in Breaking Bad, the show would have to make a choice about whether to portray that character trait positively or negatively. But we've already seen how the show portrays characters who purport themselves to be guided by strict moral compasses. The mustachioed twerp in this clip repeatedly espoused quasi-religious messages of forgiveness, but all this does is make him look hopelessly naive in the show's world.
Simply put, it would be hard for a show like Breaking Bad to portray Christians in a positive light, and even if it did, then it would come across like it was shilling for Christianity. So the answer is to just not address it at all (not explicitly, at least). And quite frankly, putting a Christian character in the show who actually acts morally would ruin the entire point of the series.
I also can't help noting that The Wire repeatedly presents support groups in a much more positive light, and that it's important that there isn't some mealy-mouthed pseudo-clinician present to delude people into believing that self-acceptance means that there is no content to their choices. It's also significant that, on that show, these groups almost always meet in churches.
The wire is fairly positive in it's portrayal of religion even if it's not a real core part of the story until the latter seasons. The black church is portrayed almost completely positively as a pillar of the community with a pastor being heavily involved in community projects and proving some of the few philantrophic services to actualy reach the underclass it explores.
https://thewire.fandom.com/wiki/The_Deacon
