I feel that the deck's average cmc is way too high. You don't have a whole lot that you can do before turn 6 and very little of that is actually ramp (1 x
2 
Post 
aside). For that matter, with so many colorless-producing lands, the risk of color-screw seems incredibly high to me. You need to lower and balance out your curve. Your end game is impressive, but everything until then seems lacking.
Also, I think that you need more 3 and 4 ofs of important cards in your deck. If you want to win through
Triskelion 
/
Mephidross Vampire 
, than you should either have more than a single copy of either one in your deck or you should have more ways to tutor for them.
I don't understand why you're running
Vault of Whispers 
. I don't see any benefit of using it over a pair of
Swamps 
and it needlessly opens you up to artifact destruction.
I do love the
Glissa, the Traitor 
package. Recurable removal is incredibly powerful. As long as
Glissa herself doesn't die it's going to 1) kill most anything that frightens you but 2) make you an obvious target. This is where lowering your curve to protect this combo or yourself can be extremely helpful.
If you're already running
Glissa +
Executioner's Capsule 
, do you really need the
Putrefies 
or
Sever the Bloodline 
s? I understand nuking a troublesome artifact, but that just seems like an unnecessary inclusion.
