This is a great clarification of some tricky issues. Theology seems to me well combined with an existential perspective. In fact, theology was always properly what we now (or used to) think of as existential. "Spiritual" is synonymous with "existential." Tillich seems to have wrestled with how to combine Heidegger's existentialism with Christian faith. (And some critics of Heidegger said his existentialism was a metaphysical or philosophical reworking of Christian theology.)

Personally, I don't trust these kinds of pat, all-embracing systems. They might be helpful as far as they go, but they're likely to oversimplify.

And I think a key issue for an existential theologian is the relevance of stories and specifically myths. What's the existential role of fiction? Tillich dismisses exoteric theistic stories, as he should. But what's the status of his model of history, politics, religion, and so on? Is it just another story or is it supposed to be scientific (falsifiable)? What kind of stories do enlightened philosophers and theologians tell?

I'm thinking about this recently, as I'm writing a series on the cycle of the hero's journey.