http://blog.ubi.com/assassins-creed-unity-9-things-need-know/
controlled descent sounds fantastic. I love the hay-bale jump, but it's good to see they don't want to over-use it any more.
also the Adaptive Mission Mechanic sounds insanely ambitous. I hope it works out, I've wanted something like this in AC for years.
skill trees/customization focusing on the different playstyles you may want to use.
Modern day is "even more different" than Black Flag's. Very interested to see what that means.