You people that hate RDR because "there's nothing to do" have to understand that not every game needs to be San Andreas, especially since it's a completely different series. I'll argue about all the crap GTAIV removed from GTA:SA, but with RDR Rockstar wanted to make a very specific experience, and they accomplished that. You aren't going to be flying planes into crop harvesters while escaping Area 69 with alien tech. It's a Western. Yes, there's a limit on missions and activities you can do compared to a modern day setting, BUT THAT"S THE POINT. It's a period game.
At the same time, it's not a perfect, and it was their first real attempt at making an open world western. I'm sure a RDR sequel will add lots of new mission scenarios, new side activities, etc. etc. Even still, if you don't enjoy the setting, you probably won't enjoy the sequel as they'll be working with the same era specific restrictions.