And I don't think that it's unrealistic for religions to exist, even in the distant future or whenever the show takes place, with all of their advanced technology. I would be very surprised if religions died out in our civilization, at any point. Old ones would simply get replaced by new ones, but the need to believe in something would still likely compel a healthy portion of the population. And apocalyptic events, such as the start of BSG, would still lead to increased religious zealotry. The fact of the matter is that the last remnants of humanity would suffer from political disputes, infighting, bickering over minutia, other such matters, and that people generally are very flawed and often unlikable individuals. But that doesn't mean that it makes for pleasant or easy viewing. And Roslin most certainly embodies that.