Dune, although it is a subversion, is pretty much a typical hero story and really lends itself to a game adaptation. That's not the case with its sequels. There's no suitable protagonist unless one were to make significant changes to the story. Paul's life ends in tragedy. and nobody else is really suitable either.
If I were to make a sequel to BtD, I would set it between Messiah and Children and make it about Alia's rise to power. Her taking over House Atreides, eliminating political adversaries, isolating the twins, squashing dissent, setting up a theocracy, expanding her vision and becoming the queen bitch of the universe. Lots of potential for sexual exploits, like in the source material. Her genetic memory of the Baron could be her sidekick/advisor.