11 years later and Assassin’s Creed Unity’s Crowd Bulk System is still the best crowd system I've ever seen.
NPCs near the player had 300 animation bones,acted independently, and reacted in full detail, while distant ones had 11 bones and moved in simplified groups that followed shared rules. They would blend up and down as you got closer.
This sorcery along with AI scaling, kept THOUSANDS of characters moving semi-naturally, creating the illusion of living crowds without giving us garbage performance. What I would give to see this tech in more modern games, Final Fantasy towns especially.