I understand the complaints about the controls but it is the most immersive and alive open world I have played. I find myself caring more about side characters than I do the protagonist of many games.
It was such a joy to explore this world, much better than 99% of other open worlds out there, and that is thanks to how immersive and lively it is.
Most open world games will follow a ubisoft style formula, with basic objectives already indicated on the map, and quite often repetitive task. In RDR2, you're going to a place, and during your journey you will encounter things that weren't indicated by icons before, lot of random event that are also actually interesting and funny. It really changes the way you're travelling, exploring. It feels a lot more organic, natural, than most games.
That's also without even talking about the evolution of the world, how you can follow NPCs and see what they're doing, their reaction to you, actions you did in the past having an impact and triggering something else in the future, houses getting build and being able to see the progress on these constructions during the course of the game, the forest with the lumberjack camp getting emptier and emptier because they're cutting trees, and there are possibly 100 more examples like this.
It's a special world to explore, it feels like an actual world you can explore rather than just a map you have to "complete".