Hot take - I hope when Red Dead 3 does come, it has absolutely nothing to do with John Marston, Arthur Morgan, Dutch van der Linde or any of the other characters we've already seen.
I hope it's a completely new and unrelated character with no connection to the past games, set in an earlier time before trains and large scale industrialisation. I want a map featuring large areas considered "Indian country" where you are always under threat from defensive natives.
I want wild, open and sparsely populated country where NPCs are few and far between - enough to keep it interesting, but not so many that there's a random guy on a horse every time you turn around. I want prairie country where you can feel like you're lost in the long grass, a million miles from civilization.