Open worlds usually suck because they are empty, or there's nothing really to do but collect trivial stuff. Or solve absurd puzzles that have nothing to do with the actual world and just make you think about how something like this would even work in these ancient ruins. Just padding to lengthen the playtime so you won't just run through the main story.
I say that, and yet I love every bit of FF7 Rebirth to the death. Go figure.
Witcher 3 made the open world believable and naturally flowing and things affected other things, there was actual writing there. You had great freedom in what to do and when. With actually meaningful choices many times.
The Fallout games have had good worlds, in the sense that every map location has something to offer with regard to the world building, or good loot or something. You could find hidden quests where you least expected them. Or at the very least some environmental storytelling, a rare item or resource, or a hint about another location. Most places were actual buildings that sat naturally in the landscape and were believable, with some caves and mines to boot. There were sometimes collectibles too, but not a thousand of them and you actually had to find them yourself, which made it feel satisfying when you did.
I don't know if I have a coherent point, just rambling I guess. But when you have limited resources to make a game, make a smaller world with really good stuff rather than a huge world that is empty, or full of meaningless collectibles. Unless you are making an FF7, then do what you want.







