Hi Coldfire0,
if you want to improve your deck I would suggest focusing on those cards you really want to play/being able to play during each match.
However, if your main discard outlet is
Miasmic Mummy, up her to a playset, it will be easier to draw it each game and play it aswell.
I would cut
Grave Betrayal cause of its cost of 7 Mana, this Effect is done by many other cards much cheaper and better (like your
Rise from the Grave).
The Main question is, which format do you want to play this deck in?