Are you sure?? So, look at this and tell me, What can I do to improve this deck?? Mr know-it-all! I tried everything, several combinations to make this deck work, And the result was the same...Now exit the internet and go ask your mother to make some milk for you...by the way, this doesn't matter anymore, I'm running Mako's deck and I was able to climb from plat 1 to legend 1 in just over 1 hour.
So sorry, but Gravekeeper's deck helped me to gain my ranks this season. I got Platinum rank, and this is my first time to achieve this rank ('coz, I am just a newbie). I managed to get through to tough decks like, dragon decks and the famous, harpie hunting ground. So... Therefore conclude, Gravekeeper's deck is still a great deck.
I would run three Oracle and no double summon at all. Instead try out Gravekeeper's Priestess and my new favourite card: Super Rush Headlong.
I personally run a different GK build because I don't own 3 mirror walls :D