Trevor,
Poetics was not an ornament for the post-Being and Time Heidegger. Poetics meant Holderlin. Heidegger went on and on about the Germans needing to understand the historical significance of Holderlin's poetry. It stood for, or signified, a great turn, a national awakening for Germany.

Poetics was the core of Heidegger's late philosophy--the one developed after his engagement with Nietzsche.

Holderlin's poetics shaped the way Heidegger's philosophy engaged with politics. Germany's future lay with a going back to the Greeks as a way of moving beyond liberal capitalism and Soviet communism through the creation of a national language.