You know, they updated the other day saying that crowd sizes are not the problem and do not effect framerates. I know I'm not in the office doing the testing, but that just sounds like bullshit. The crowd is either hampering the game because of GPU needs or CPU needs. It's most likely the CPU since both consoles have relatively weak CPUs. However if that's the case then how is it not crowd size that's the problem? The crowd HAS to be consuming mountains of resources SOMEWHERE. They aren't just free of cost.
And it's most likely all of the AI that has to be loaded into memory. If this isn't the case then why REQUIRE at minimum an AMD FX 8350 on PCs? That's a bit of a beast for minimum specs. I think they just don't WANT to lower the crowd size. They feel like it's so essential. It's not. You could have 2/3's as many people and get the same astethic they were going for. I mean no one had problems with the amount of people in previous Assassin's Creed games. Literally NO ONE complained about the crowd size. It's just like Dead Rising bragging about 5,000 zombies loaded all at once. Why? You couldn't even see or fight them all at once. Hell, people actually said there were too many zombies even back in Dead Rising 2.
Back to Ubi, for god's sake stop using 50,000 draw calls. DirectX wasn't built for it. Learn your limitations. The game doesn't need 50,000 draw calls at once. There aren't 50,000 things that can be seen at once for you to need it.