One of the first things people judge open world games by is the size of their maps. Red Dead Redemption featured a pretty large overworld, however it didn't break any records. The border state and Nuevo Paraiso made for a sufficiently large and detailed map and it was definitely amongst the best and most memorable of its time though.
More recently, with GTA 5, Rockstar showed the world just how well they can nail open-world maps (but really, they proved that long ago with San Andreas). That said, no open world map has managed to be as vibrant, as filled with intricate details, as GTA 5's Los Santos and Blaine County. The tiny tidbits, the attention to detail and the scale of it all makes for an entirely immersive experience.
Sure, there are bigger maps out there - looking at you, Just Cause 2 - but sometimes size isn't everything. However, in the case of Red Dead Redemption 2, chances are we'll have a new record-setter. The reason behind this stems from the game's setting, the Wild West. In the case of GTA 5, you have a modern setting with highways, a large metropolis taking up the southern half, and all kinds of ostensibly modern things littering the landscape.
In a Wild West setting, there is only so much you can do. Sure, the folks over at Rockstar will likely get creative, but in the end, resources won't be spent on detailing a massive, sprawling modern metropolis. The Wild West, by virtue of its location, is characterized by a lot of open nothingness. While, from a game design standpoint, a big empty open desert would be a bad choice on its own, RDR2 is guaranteed to be more wilderness than urban.
With so many resources freed up, Rockstar will likely ramp up the size of the map dramatically. Sure, they'll still probably craft the single most detailed open world in gaming to date, but it's easier to add detail and immersive little touch-ups to a Wild West setting than to a modern day setting. While it's obvious that the map won't reach the size of something like Daggerfall, we might still see a map that one-ups Just Cause and other competitors.
Some might think that this question has already been answered by the leaked map from earlier this year - thing is, that has been proven to be a fake leak thanks to Rockstar's wording of the official game announcement. The leaked map shows an area to the southeast of the USA while the announcement blurb suggests that the game will take place in the Midwest.
How big do you think Red Dead Redemption 2's map will be?