I didn't know about the Abstract-Negative-Concrete formula (so much for my naïve days as a young socialist), but it makes sense from an audience's perspective. We enter the theater in an abstract state of mind (much like the protagonist, who exists in a stable but unsatisfying phase). Then we are shocked out of our abstraction by the call to action (end of Act 1). But the negation that progresses through Act 2 isn't inherently satisfying until we reach a balance (neither abstract nor negative, which is a kind of concrete state) by (your ideas here) integrating with our shadow side.