There really is a lot to Unity, but there just isn't any escape from the traditional AC stuff here. You're stuck in one (huge) city doing AC parkour, AC combat, AC stealth, and the same kinds of activities that have been with us since the first game. I think the most fun to be had is in the co-op missions and heists, with or without other players. These present more varied and interesting objectives, and many more difficult guards than usual. Another plus is Arno's RPG-like development, based on gear properties and earned skills. There are 4 currencies, with 2 of them needed for something akin to leveling. Livres buy stuff like gear (weapons, clothing) and consumables (blades, ammo, medicine, etc). Sync points, the most scarce, buy skills--permanent enhancements. Articles of clothing will enhance all your character's attributes in varying amounts, depending on the set type (e.g., military, phantom), how advanced it is (e.g., master, legendary) and where you wear it (head, chest, etc). Examples would be extra health, extra special throwing blades, bombs, lockpicks, how well eagle vision works, how hard you are to detect, and so on. Skills are things like health (HP), attack strengths, and special abilities. These sync points can only be earned in story missions and co-op/heist missions. And you only get a few at a time. Side missions will not cut it. It took me dozens of hours to ramp up Arno to the near maxed-out state he is in now. It's a good system that makes you feel like you've earned your godly powers.
I only have the last sequence to go through, then I'll be done with the story. I've spent much more time doing other stuff (side missions, renovations, collectibles), and only recently have I discovered how good the co-ops/heists can be. Just played one such mission tonight with 3 other players. That was insanely fun, even though I had no idea how to communicate with the other guys. The Kinect is hooked up, so there's a mic. But unless the party chat comes over the speakers, it makes no difference. I'm not a fan of headsets, or chatty multiplayer with strangers. But this was very cool. I need to do it more often. I'm so chicken, though, like I get stage fright when I'm in an unknown crowd.