There seems to be quite a few cards that are in there for value, but don't really fit. Bloodghast can work with fetch lands and as discard to Liliana but it doesn't really do anything for you. Fatal Push really isn't great outside of standard imo. Beth's Verdict and Lifebane Zombie should probably both be dropped for 2 more Temporal Extortioms, and I would have some life gain to counteract Phyrexian Arena.
Bloodghast also gives me a source of early turn pressure. I really like Gatekeeper and have considered it before. I might give it a try, I could see moving it into the Push slot or the Geth's, but
Fatal Push is amazing in Modern and even better in Legacy!{Not great in edh lol} Lifebane was originally in the side, but has been so useful that I put him in the main. I wouldn't mind trying a second
Temporal Extortion, it has overperformed. {I have to hunt it down though}
One of the main reasons I settled on the Arenas is that the loss of life is negligible. It has always provided far more value than detriment.
Also, the ability to lock out grave strategies in modern right now in a one-sided way is good in modern right now in general, in my particular meta it is especially valuable. [another copy of Nykthos will be nice as well.]
The Cryptghast is just too slow for it's mana cost. The
Marshmist Titan was a nice addition.... Thanks for the feedback.