I don't know what route Rockstar are gonna take with clothing and customization in Red Dead Online. I'm hoping they go with something similar to GTA Online's Character Customization but they will need to tinker with the format and make it something fresh and different, maybe they could give the player a variety of different holsters to choose from.
It's also a Western game after all so it would also be nice to see weathering affects on clothing because although having only set characters to choose from in Red Dead Redemption's Multiplayer wasn't the best it meant all the characters we could play as were extremely detailed with dirt, dust, stains, ripped clothing etc.
I don't know if anyone here has seen or played TC's Ghost Recon: Wildlands but the game has a system whereby dirt and dust will accumulate on your clothing, something like this would work so well in Red Dead Redemption 2.