I think someone should reboot the Dune RTS game from like 30 years ago. I played it as a kid on my Sega Genesis, and right now it's a ripe time to do it. Interesting parts:
- feels like C&C, but with spice worms
- lots of factions, but could stick to three: Atreides, Harkonnen, Corrino/Emperor (optionally add the Fremen as a fourth)
- cool, unique tech and setting
So, here's what I suggest:
- copy C&C gameplay with updated graphics, and swap units appropriately
- add spice worms as a "random" event based on greed (keeps stronger players in check)
- balance like in Starcraft - harkonnen are like Zerg, corrino/empire are like protoss, and atreides are like Terran; Fremen faction could work like Zerg, in which case harkonnen works more like Terran
I think that could sell well.