1 - Graphics like the AC Unity (NextGEN)
2 - Hidden blade
3 - More stealth gameplay
4 - No fantastic, no creatures.
5 - Medium-sized non-empty map.
6 - Rope dart (for fight and for jump) ( https://assassinscreed.fandom.com/wiki/Rope_dart ) e.g. Throw a rope to your opponent's foot and lower it to the ground. And choke him with rope.
7 - And fight like AC 3
8 - Add - brotherhood.
Note : https://www.youtube.com/watch?v=-0tR-iyl8xA watch this beta versian AC 3
They are removed Rope tool for fight.