I'm completely head over heels for this archetype in standard. My meta consists of a large number of Naya aggro and midrange decks, and this build has had considerable luck against them. I've taken second at four different FNM events, and feel a lot of potential for this type of build.
I'm deciding to play a bit more creature heavy, since I only have one Snapcaster Mage. In my experience, control builds give this deck a hard time as a result. While the printing of Glaring Spotlight makes it much harder to kill people with Geist of Saint Traft, I feel that the deck still preforms well. I've had great luck with tempo spells, so for now I'm sticking to it.
My favorite Gatecrash additions bar none are Boros Reckoner and Boros Charm. Those two cards in addition to Azorius Charm enable a hilarious infinite life gain combo. In response to the Reckoner being dealt damage, you make him indestructible with Boros Charm, then give him lifelink from Azorius Charm. Simply use Reckoner's triggered ability to shoot himself, and repeat the process as much as you like. If your opponent won't swing at you or block the Reckoner, you can initiate the play yourself with a burn spell.
I've had great success with
Lyev Skyknight
. At best, he's a tempo spell that allows Geist to thump for large damage, and given the chance, he's great with Restoration Angel.
Silverblade Paladin lets Geist, Thundermaw Hellkite, and Aurelia, the Warleader thump for enormous damage, and tends to make a Skyknight much more threatening.
Feeling of Dread
has been an all-star for me. Brutal tempo piece, good stalling mechanism, and can with you the game with Geist getting swingy. I have high hopes for Aurelia's Fury as well, as a tempo piece and as a burn spell.
I'm debating attempting
Mugging
over
Pillar of Flame
to force more damage through, as well as Thought Scour in combination with the bounce to the top of your deck mode on Azorius Charm to help fight off Obzedat, Ghost Council. Any opinions?
As ever, all feedback is welcomed and returned(: