First, i have to say that this game doesn't deserve a 10, it's the buggiest AC game to date, but i've watched a "making of" doc about it and understood the kind of work behind this.
Graphics:
AnvilNext Engine is great - detailed weather and seasons, lots of NPC on screen and by far the greatest achievement is the FRONTIER with incredible details,animals, trees, water, mountains,caves and so on. Snow trails and water physics are just amazing.
Story and characters:
The story was ok.. it wasn't extraordinary because American history is not that interesting, personally, I prefered ottoman-turkish history from Revelations.
Even though the main character is not that likeable at first, after you complete the Homestead Missions, you get to know him better, and you empathise with him. Also, nice touch with the addition of Haytham and Connor as a child gameplay, really felt different. The villains and other characters have great personality, and Ubi managed to recreate superb history-accurate events.
Gameplay:
I mean, come on, this game improves almost every aspect of past series and adds a lot of quality content to it. Even though the cities were a little boring, the naval missions and hunting additions are incredible, while the mini-games were not that interesting. Climbing trees feels as it should, also, I found the fighting system improved, and A.I more difficult to defeat, which is a good thing. Also, I haven't touched the crafting and economy system, too complicated for me.
The multiplayer is just an expansion of the previous games, new maps and characters, low activity (maybe because they release PC version too late), also they gave a facelift to the menu with a nice dark theme.
Overall, this game did great, had great reviews, but it's somehow different from others AC games, and you either love it or hate it.
LATER EDIT: After playing the "Tyranny of Washington" DLC, I have to say it makes a pretty good story.
I liked it and I would rate it a 8.5. Even though the A.I. was a bit numerous throughout the cities (making it very hard for you to discover and collect all treasures) , the addition of the super-powers and the variety of the missions were the main positive points here. Managed to play all 3 episodes in 5:30 hours, back-to-back it's the way you want to play it.
Thank you for reading.