Brother,You guys gotta get over yourselves and use your head a little bit... If Assassin's Creed games on the PS3 and Xbox360 have no trouble sticking TONS of NPCs walking around in a city with no frame drops... it's quite obvious that the PS4 can do the same thing. This is probably just something that will be fixed/corrected in the Patch.
NPCs in Witcher 3 in Novigrad are the residents of the city, Every NPC has a house, a schedule and a life, unlike in AC:U where they are randomly generated just to fill the space. There is a lot of difference.
In this game, every NPC has a name, an occupation, a house, a family and a schedule.