Nice deck. Needs Necropotence, Mystic Remora, and probably Rhystic Study. Check out your cards and see which are redundant (i.e. theme-humping).

Manalith sucks and can easily be replaced.

Spin into Myth is easily one of the rudest EDH cards. You should look into it and Void Stalker . Diabolic Tutor and Diabolic Revelation are some good tutors you may want to look into. You may want some hand control in there to get rid of threats that havent hit the board yet, some could be Thoughtsieze, Duress or Hymn to Tourach . Thats all I can think up right now.

Oh and Mind Funeral is just a fantastic mill card.

Life's Finale with Lazav, Dimir Mastermind is broken if you can make him indestructible. Darksteel Plate with board wipes = win. plus you can tutor it with fabricate.