New Red Dead should revolve building something up. There hasn't been a Rockstar game in quite a long time where you bought properties, rackets. Starting from nothing and owning the entire map. RDR and GTA V had that stuff technically, but it was shoehorned in completely.
I want Vice City and San Andreas ownership/rackets to come back. Owning a saloon and having to recruit/manage prostitutes, owning a ranch and doing ranch shit, or being an outlaw in general with a posse you recruited. Morality system can influence who targets you and why.
Even something as simple as the gang turf/warfare system from San Andreas coming back would be nice. There needs to be more side content that feeds back to some sense of progression, rather than playing horseshoes, poker, and can I not stab my finger minigames.