You have too many Darkslick Shores for what aims to be a control deck. Fastlands are for aggro, when only your first three land plays really matter. One more Watery Grave and one more Drowned Catacomb, as well as one or two Urborg, Tomb of Yawgmoth, will give you more consistency with your mana.

Splashing white could be good - it requires a lot of tweaking to your mana base, but stuff like Path to Exile is more than worth the effort. By the way, if you do, consider playing Narset Transcendent - highly relevant +1 for creatureless decks, and a -2 that's just CRUEL with Glimpse the Unthinkable and Breaking.

Thanks square711,

I've had zero problems with the 4x Darkslick Shores (and I play this deck a lot), maybe because I don't really cast things that cost more than 3cmc or maybe I've just been lucky; but I see the potential for problems you are getting at.

Anyways, Urborg, Tomb of Yawgmoth is a great land suggestion and I'll have to pick one up asap.

Also, if I do splash white Narset looks to be a killer; much appreciation for the suggestions!