Theres plenty of ways to use Rift Valley to your advantage
Gaining life is something that The Gaffer appreciates, though its pretty easily done by sacrificing a single Food for three life
Or your deck could make interesting use of the exile mechanic to remove and return creatures to play for bonuses such as creating flying creature tokens like the Phantom Premonition deck does
Now kill anything you wish
Light-Paws, Emperor's Voice A good aura Light-Paws, Emperor's Voice is a two-mana White 2/2 that reads: "Whenever an Aura enters the battlefield under your control, if you cast it, you may search your library for an Aura card with mana value less than or equal to that Aura and with a different name than each Aura you control, put that card onto the battlefield attached to Light-Paws, Emperors Voice, then shuffle." This is undoubtedly going to be an almighty card in Commander but, given how potent the ability is, we wouldnt be surprised to see this at the forefront of an aggressive aura deck in other popular MTG formats too
Its no surprise that the recent Prismari Performance preconstructed deck was a Spellslinger one: every aspect of the archetype has an artistic and expressive feel to it, so it fits the bill perfectly