Steampunk: Arcanum is really the only cRPG that attempted this setting and while they did an amazing job on the atmosphere, unfortunately the combat was dreadful, level design was atrocious, and there were lots of balance issues. Quite a few JRPGs have steampunk elements, but generally not a big part of the plot / world.
I'd also say
Cyberpunk hasn't been doing nearly enough, even with future expansions of Shadowrun Returns and Cyberpunk 2077 on the horizon.
And I'd love to see some
space opera RPGs… Mass Effect but less Biowarey; preferrably an isometric turn-based RPG. The Mandate sounded cool enough for me to back, but it's still an action RPG.
I'd also like to see more Fantasy RPGs that are NOT of the typical garden variety based on medieval Western European folkore:
African folklore: I did see that awhile back there was an action RPG based on African folklore called "Aurion: Legacy of the Kori-Odan" on indiegogo that looked pretty cool.
Ancient Egypt: only thing I'm aware of is Ravenloft: The Stone Prophet, which I sadly have not played.
Middle Eastern:
Zaharia sounds really promising. And Son of Nor, though it's not really an RPG.
Feudal Japan: While there seems to be a fair number of Samurai strategy and action games, I'm not aware of many RPG titles. Plenty of JRPGs feature samurai characters but with the exception of Suikoden, they're usually just pigeonholed in the generic fantasy setting AFAIK.
Native American culture could also be very interesting I think. Lots of great folklore to derive from. AFAIK this has never been done.
Indian-
Unrest, as far as I know will be the first.
Basically A fantasy or historical game based on any non-medieval European culture would be most welcome.
I assume part of the reason that many non-Western European cultures haven't been explored much could be simply that any developers who aren't descended from a given region / culture would be afraid of misrepresenting it / accused of portraying racial or ethnic stereotypes. But this genre could use some more variety.