The more I look at this deck the more I love it.

Great deck! I am looking to make a zurgo deck and this gave me some really good ideas! If I were you I would add things to give vigilance, if you do you can add cards to give you extra attack steps. Also extra mana ramp would be a good add in as well. Gotta equip as much as possible, right?

This deck looks super mean, and I have a few other suggestions that perhaps you missed. The first one is Spell Snare For obvious reasons, you might want to look into getting one of those. Additionally, Remand is a very powerful counterspell that is a lot better than it might seem to be at a glance.

Next thing, I think you need to have a look at your card draw spells, because I am noticing a distinct lack of both Ponder and Preordain. While these are sorcery speed, they grant so much library manipulation and card selection that you will not regret including them.

Any particular reason why you're running Rattlechains? Geist does already have hexproof built in.

Lastly, if you can afford it, Sword of Fire and Ice is one of the best cards you can ever acquire for a geist deck.

Hope this helps :)