1) Definatly up the cost. While graveyard does have more potential, I still think this would be far more useful, especially couple with eternity and RT.
2) Name. The great prophet? Why does a prophet raise skeletons? Or how? Why does it look like that? Prophets forsee the future and thus seem more like some kind of time card (golden nymph would be most comparable). The art can stay but really rethink the name