I would add a few pillar of flames maindeck, and -2 searing spears and a couple warleader's helix.A couple Thundermaw Hellkite (instead of gideon). I also like skyknight legionnaire and spark trooper.
Permalink
Consider these 1 or 2 mana costs creatures to replace Tithe Drinker: Cathedral SanctifierVizkopa GuildmageBlack CatCartel Aristocrat Doomed Traveler I like the enters/leave the battlefield affects for this deck with all the return cards you have. I also think there's strong potential with opponent hand destroying in this deck.
I like it. Not sure if I like the Emissary in this, since it won't play into a Lotlith or Jester. Also not sure what you need to Farseek to. The highest mana cost is 3.Check out my Varolz themed deck I just made last night... it's more creature focused and has less utility than yours. http://www.mtgvault.com/runningsloth/decks/the-varolz-army/
Maybe some Immortal Servitude in place of Obzedat's Aid since you'll have so much mana with Crypt Ghasts.Also, I think I like Orzhov Charm here better than a standard removal like Murder/Grisly Spectacle