Since there is such a massive difference between Traditional Catholicism and Biblical Christianity, would it not make more sense to separate into two StackExchange sites? Maybe even 3 (Catholicism, Protestantism, Other)... Jehovah's Witness, 7th Day Adventest, and Mormonism, for example, are not Christian religions, yet questions regarding them regularly show up here.
I understand the confusion as all of these recognize the Bible as one of their religious texts, but they are all different. Mormons, for example, have historically distanced themselves from Christianity (though in recent years have started to identify as a Christian denomination).
I just think that the current system of lumping them all together is confusing and makes finding a relevant answer, or even asking a relevant question, very difficult.