Well, Im not someone who judge after the first few hours of playing. I played the whole game and carefully noted positive- and negative aspects of the game. The positive aspects should definitely be mentioned because they are not self evident. The negative aspects should be a incentive for the dev’s to polish their work.

achievements of unity
+terrific graphic quality of the ingame cutscenes (face, skin and blur effects)
+beautiful warm sunlight/shadow effects (global illumination)
+birds, animals and insects make the world look more believable
+I noticed that you can still hear the crowd noises in the backstreets (quiet) and it gets louder the near you get to the streets (this could be even more improved)
+clothes of the main characters look extremely realistic (especially arnos while moving)
+overviews before the infiltrate missions
+beautifuls interieurs
+beautiful color effects from the glass of the churches and great architecture
+crowds in the streets makes it possible to “dive” in
+when detected not every npc in the game knows your position and wants to kill you for no reason - like in the last AC game. Now only the people who can actually see/hear you are alarmed. Only the bell can call other people – a huge achievement.
+coop gameplay is a great new online mode

deficits of unity
-water animations are still terrible (seine looks stiff)
-no indoor shadows from light sources or indirect reflections from the bottom
-no “seamless” speed control/ different running speed levels (slow running when pressing R2 a little)
-no collision animations with crowds when jumping from anything on a person
-poping up crowds with slowly loading clothes/shadows textures
-crowd animations still not fluently
-really bad gun aiming system (impossible while fighting)
-maybe too much crowds in doubtful areas..
-still many street sound imitations (would be nice if the sounds can be tracked/ have a real source)
-on some trees the leafs are stiff and in some the leafs + shadows are moving
-when going into blue areas instantly getting killed for no reason – nobody would instantly attack unarmed people – the surprise effects should be a basic element of the game
- no wind that makes your clothes fluttering in the wind when being 50m over the bottom at a sync point or on buildings (this should be done since the couple of ac games)
-carrying body should be a “skill” that can be unlocked
-the hot air balloon from the mission should be available as vehicle
-online free roaming for 10-20 people?

Im sure there are many more