Depends on the game. Something like GTA definitely benefits from it. More space to drive/fly around makes the game more enjoyable. GTAIV really suffered from a lack of space, diversity too. With larger worlds there is more room for diversity. Of course if it's all the same then a large world is kind of a waste, but it gets boring seeing the same things over and over so moving to new and different locations is good.
Bet Shiken that COD would outsell Battlefield in 2018. http://gamrconnect.vgchartz.com/post.php?id=8749702