After doing a bit more experimenting and looking at some well-performing decks in the format I think I've figured out some improvements.
I've moved 3 out of the 4 oblivion rings in the deck over to the side board, replacing them with 4 copies of Journey to Nowhere to keep things a little bit faster. Enchantment based removal is more important in the deck now, as I've adopted a bit of an enchantment sub-theme.
I replaced 2 shelters and 2 Marshaling cries with 4 copies of ethereal armor. The armor also synergies with the 4 copies of nyxborn shieldmate and 2 copies of Hopeful Eidolon I threw into the main deck. These creatures are good for not only powering up the griffins in the late game, but powering up the armor as well.
I've also removed the copies of Banishing Light as it rarely, if ever, came up as a useful draw.
I'm considering splashing green for rancor, as I think it would be the push necessary to send this deck over the top. We'll see how this weekend's Pauper event goes.