Funny you say that, I actually just recently removed a little ramp from the deck. The issue I have often have, is in my mid game, I start to run out of recursion options if I intend to go heavy on my scarab gods active ability which exiles my yard. I understand you could, and most likely should be targeting opponents creatures as well if they are indeed in the yard, but that is not always a valid option. Bottom line, I had simply too many rocks hitting the field. Zombies, are a slow, lumbering deck, at first.. and should be played as thus. You have to be able to utilize your scarab god, he often goes to your hand when he is removed, meaning no increase in cmc since he goes to your hand. Scarabs god scry/burn is absolutely silly, and should absolutely be your main focus when playing him, not his active. You should be sitting quite comfortable if you hit even a single rock, and load the field with zombies.