Never felt you were making it up, and it's obviously there. But I can also honestly say that I never had ANYTHING like that in over 70 hours of playthrough. No matter how crowded, intense, or chaotic the scene was. And I was often being knocked around plenty, set on fire, smacked with rocks, pelted with ice, while five machines were trying to shred me, all at the same time. It was rock-solid for the entire 70 hour experience, in every town, interior, and battle.
I really don't know what to tell you on performance other than I've not seen it that bad for anyone else. If anything, the game's performance has been held up as a high-water mark for open-world games, and every professional analysis has pegged it as very smooth, with the most egregious dips in the utmost demanding scenes at worst at 26 fps instead of 30 (and that was during the Nora festival which just filled the scene with NPCs).
PS4 and Pro Performance
Perhaps it's something with your PS4 (just because it runs other games smoothly doesn't mean the memory dedicated to Horizon might not be wacky; games flex the PS4's muscles differently depending on the demands), and I don't want to presume you got a defective version of the game. Token troubleshooting tip is to power down the system entirely for up to 12 seconds or so.
Though, here's a big question... what kind of a harddrive are you using for it? Default, external, SSD? I'm using a normal 2TB Seagate one I replaced the old one with, and the performance is solid on that.
