I'll admit I've got under 10 hours of gameplay in but from what I've seen, it's enough to give a good enough review. I will say though that because Ubisoft insists on putting out a new Assassin's Creed title every year, I'd given up the series for a while; I just needed a couple of years without playing a series I loved. And also this comes on the heels of finishing Assassin's Creed Rogue.
I'll be the first one to say that Assassin's Creed needed a revamping; putting out a new game every year will make everything seem stale. However a lot the changes that were made, and I'm using Rogue as my comparison, weren't needed or have taken away from the overall experience.
The Good: With Unity being the first in the series on next gen consoles, the graphics were upgrade and they look fantastic. Everything looks better than in previous games. Even the map going 3D was a nice touch. Then there's a whole bunch of new side activities that, from the couple I've done, are all right.
The mediocre: So far combat isn't as smooth as in previous iterations. Maybe it's because they introduced new mechanics or targeting system but it seems that entering combat is a bit more of a challenge or switching to a pistol/ranged weapon isn't as smooth as before.
The bad:
First of all the new parkour system may be more precise but precision in this instance isn't all that it's cracked up to be. Other versions, going all the way back to Assassin's Creed II made parkour relatively smooth. There was something fun with running up buildings and then across rooftops. In Unity, there's been another layer of controls, so to speak, added so much of that smoothness and fun is gone.
Then we have the glut of information, options, and menus. By this I mean trying to navigate many of the menus means coming through numerous sub-menus to get to what you actually want. Then there's the many, many, gear options (weapons, colors, armor), skills, etc., etc. Part of me appreciates it to a certain degree but part of me says it's just too much. There's something to be said for wanting to have options for players and then there's having too many options.
I'm also going to call out the co-op missions. I'm not that kind of player. I don't play games with others; I'm a lone wolf in that regard. So I don't want to have to play co-op missions just to get all the gear. If you're going to give gear for doing those missions, I don't want to know it. Plus from what I read on Gamespot about having to be linked into Initiates just to get other gear is equally frustrating.
And finally from what I've read the whole modern day parallel storyline has virtually disappeared. Personally, while that parallel storyline may not have been as interesting as the historical one (that is after Assassin's Creed III), that storyline helped anchor things and tie it all together between games; especially since the primary protagonist changes. I just adds that bit of continuity needed to tie a story based game together
So my final thoughts. Assassin's Creed was in need of revamping. With the notable exception of the graphics, most of the changes made have overly complicated things. Hopefully Syndicate puts a better balance on everything.