It seems to me there are three quite distinct activities relating to religion at the post-graduate level.
A. The study of the origins of religious texts by the historical critical method. This could include the texts of religions such as Mahayana Buddhism, the Vedas and the Gita in Hinduism. But in practice this discipline is mainly focussed on the New Testament. And there seems to be less and less demand for this as an academic discipline.
B. The even-handed description and comparison of the inner logic and experience of various models of religion and ideology. This is what I call model theology (I distinguish 24 basic types of religion and ideology, see God of Many Names chapter 2 & 3). This discipline requires a willingness to give an account of each type of religion or ideology with sympathy and without caricature (from the inside) in a way which a devotee of that form of religion or ideology would accept as a true account of what he or she believes. I imagine university students would find this to be a useful discipline to engage in.
C. The articulation of one particular form of religion or ideology
with a view to training those who will be involved in teaching and propagating
it. This can be done at the post-grad level for Islam, various forms of
Buddhism, Hinduism, Marxism, Existentialism, etc. and each of the main
forms of Trinitarian Theism. I take this to be the function of a Seminary
set up to train students for Christian ministry. Obviously this cannot
be taught by someone who does not believe that the Christian faith is worth
preserving or propagating.