I could live with that as long as the actual teaching of each school of thought is presented in a truthful and unbiased. Speakers or representatives from each ideological discipline could present their cases while letting the students decide what is true or false.
Speakers and representatives from each ideological discipline may not be needed; in fact, might get in the way. For example, if I taught such a class, I would teach the Bible from the historical and literature perspective, and then break the students into small groups where they could discuss any religious facets or implications among themselves.
I wouldn't mix the Koran, Buddhism, and other religious texts in the same class, because that would be rather like mixing history and English in the same class. Yes, it could be done, but each has enough material that mixing them all together wouldn't do justice to any of them. Offer each as an elective. If the interest is there, have the class. If its not, don't.