Assassin?s Creed Unity Co-op Heist Mission Commented Demo [US]
The Assassin's Creed Experience - Comic-Con Day 3
Assassin?s Creed Unity Arno Master Assassin CG Trailer [US]
The Assassin's Creed Experience - Comic-Con Day 2
This article has a few details. I don't know if it has already been posted, so sorry if it has.
"The other big revelation is that crowds will now centre around specific points and events and then disperse. Just like real crowds"
I found this part interesting but could also be annoying if your trying to escape without falling over.