Witcher 1 and 2 weren't sand box in any kind of way. When you have 20 NPCs to work with it is pretty simple to give them a schedule and have them do stuff like go into their houses when it rains.
I haven't played a sand box open world game where random NPCs behave in realistic ways. Did CDPR set this expectation? I didn't follow much of the hype.
It's not so much about behaving realistically as much as well...behaving at all. GTA3 NPC's react more to the players actions and that was taken into account when developing the game.
With Grand Theft Auto 3, DMA has programmed its non-player characters, the artificial intelligence (AI), to perform several acts that simulate Good Samaritan behavior, but it's also programmed them with personalities, which means quirks, oddball behavior, and therefore even some surprises.
The pedestrians, or "peds," as DMA called them, in this game are programmed to act like good, law-abiding citizens. OK, well, the ones that look they are good law-abiding citizens usually are the ones who are good, law-abiding citizens, and the one who don't look the part, well, let's say you might expect different, perhaps even violent behavior from them. In Liberty City, the peds walk around in the morning and talk to one another. They are programmed to react to one another, and to you, too, depending on your actions. In Driver and Driver 2 cars never hit pedestrians. As soon as a car is inches from a ped, bam! He runs away. In Grand Theft Auto 3, the peds may fight back if you attack them! Here's a good example. You can carjack any car in the game -- a cop car, bus, taxi, boat, limo, sports car, if it's in the game, it's yours for the taking. But depending on the non-player character in the game, he or she may react differently. In some cases, you open the door, grab the driver and throw them onto the ground. They yell, scream, or curse you. But some will simply lie on the ground afraid, while others may quickly get back on their feet and fight back. Yeah, they are programmed to get mad!
When it comes to recent games Watch Dogs Legion NPC's all have dynamic reactions to the player and also have day/night cycles along with relationships to other NPC's. I didn't expect that level but cars being able to drive around a roadblock seems like an easy enough expectation to hit.