I almost never research divine right. I don't care about the spiral minaret or versailles, the AI can have them. I think NOT having it is a valuable diplomatic tool. Instead of having tech hogs like mansa and zara coming begging for your newest tech all the time and either giving it to them or taking a diplo hit, they'll say "hey gwynnja, check this out: I'll give you divine right and you give me rifling and 8 billion gold. sound like a deal?" then you can just say it ain't happening with no penalty. it's rare to have a tech as completely useless as divine right that you can always just say no thanks and not lose points, but if they don't have something they think you want then they're bound to try to get you to gift it to them.