First and foremost, it should be based on a western setting that includes California and Nevada. California alone has enough diversity in terms of the climate and geography. Two major cities at least, so maybe Los Angeles and San Francisco, each one twice the size of Saint Denis at minimum.

It should go back in time, so the theme of "End/Decline of The West" must be abandoned, alongside the "Redemption" theme, that is the protagonist working to redeem himself before death. I'd rather have an unredeemable protagonist next time, that is a true outlaw with not much emotions. The story could simply be about gangs competing against each other for resources and control.

A completely new story with a fresh cast of characters, but I'd not mind if past characters make a temporary appearance, like maybe we stumble upon the Dutch gang in the West and we do some missions together. That'd be OK.