Variations I can see
Sidethought-I'm guessing if they name the Prophets there's a few we won't see. (Founders of the 2 big monotheism faiths-one for threat reasons, the other for the God not prophet argument...and their role can easily be taken by some of their immediate successors)
When settling (first issue where do they settle, on a tile or in the appropriete district?-ie are they a tile improvement or a building)
-fairly easy-adjacency/terrain of that city bonuses, or bonuses to their "off" yield, or slightly different bonuses...on building is gold +50%, +3 gold, the other is +40%, +7
When popping (I really hope "pop value" is fixed like with Great Musicians...so no more storing the GS up to the end)
-bonus specific Eureka moment (if they are tied to eras-giving a second way to get a Eureka)...or just bonus advancement towards a particular tech/civic
-specific beliefs added to your religion (prophets)
-bonus other yield (Merchant Gates provides money and science when popped)
-bonus base yield for certain goverments/policies in place/other conditions
-GGen: different types of bonuses/unit specific ones (ala Khan)
What's really important is how they do the 'wait' feature,,
Do you just keep your points, wait for someone else to buy, and then pay the higher price?
OR
When you get enough, trade your points for a 'choose great scientist' token and the cost goes up for everyone (but it doesn't go up when you trade in your token)