i find it difficult to pick really, because i find it dependent on the quality of the game, and in this instance, the quality of the map design. if the world is something that appeals to me, either will do.
I'm playing Horizon right now, and the map compared to other big open world games like The Witcher 3 is rather small. But there doesn't feel the need for it to be bigger - the settlements aren't particularly interesting or interactive, there isn't a lot of NPC's with important things to say, not that many side missions, only one merchant in each place that stocks everything. So I'm happy for that more focused map design, where the world is great to look at but there isn't too much of it. On the other hand, something like Skyrim is huge, and there are big areas that in the larger scheme of things are pretty aimless, but the world is so gorgeous that having a stroll around isn't boring, as there is always an NPC to talk to with a side mission reasonably nearby. So I enjoy both approaches when done well.
On the flip side, if the world isn't particularly interesting, I would definitely prefer them smaller and more focused. As much as I like the GTA games, the main thing that makes that franchise great rather than outstanding is that I don't find the maps that appealing. I never think of just walking or driving around in a GTA game, and the maps are too big for my liking.