The Oracle is still going to provide pretty solid return on investment there. If they're both gone, then there might be an argument for a GM. I didn't consider the possibility because I figure if you're going for you're burning a GE from Meritocracy on one or the other. However, I suppose that on Deity you could find yourself needing Patronage, Rationalism or Freedom policies in a hurry, short on the with which to get them, and not having an early Wonder available. In that situation, the GM might be viable.