With Kant's kind of natural or rational approach to religion, what went out of the window were things like sacraments, dogmas, liturgies, hymns, candles, miracles, sacred stories... in short, what Peter Lourdes likes to call the 4 C's: creeds, codes, cults, communities - what he also calls the 'external trappings of religion.'
Peter is not the only one to demote the 4 C's in favour of what is 'truly significant' - the inner core of religion, perhaps described as 'religious experience.'
Two comments. First, it is good to be aware that this kind of (now very common attitude within the Indian Church) has roots in the Enlightenment championing of a rational religion, a religion within the limits of reason alone. Second, this kind of a religion just forgets that we human beings are more than reason, and certainly more than 'pure reason' - that we are flesh and blood, embodied, incarnate as well as spirit... The 4 C's are very much part of the wholeness of being human. But not even Heidegger, that champion of the return to the concrete, saw his way to affirm such a religion - though, enigma that he was, he did manage to evoke powerfully and beautiful some of what he had spent his life excluding, in his very beautiful and poetic later reflections on poetry, on poets, and so on.