I would cite AC3 as one of the Ubisoft multi-studio games that turned out well. It got an 85 meta and I personally liked it more than the previous 2 AC games (Brotherhood and Revelations), as well as Assassin's Creed 1. I can see how communication would be a nightmare though, and the game did suffer some because of it.

As for AC Unity, it seems like short dev time was the reason for it's issues, not the fact that it was multi-studio. From what I've heard the first year of development was mostly just the programming team making the new next-gen engine, so of the game's claimed 3 years of dev time, only 2 were used for actual development. An Ubisoft dev recently said that they realized that AC Unity wasn't ready for release, but decided not to delay it because it also would have meant delaying every single other AC game that was in development already. Delaying AC Unity to 2015 would have meant delaying AC Victory to 2016, and the AC game after that to 2017 (AC Japan if rumors are to be believed). The AC Unity team didn't want to have to force the other AC teams to delay their games as well.

I would cite AC3 as one of the Ubisoft multi-studio games that turned out well. It got an 85 meta and I personally liked it more than the previous 2 AC games (Brotherhood and Revelations), as well as Assassin's Creed 1. I can see how communication would be a nightmare though, and the game did suffer some because of it.

Nah, that's Revelations imo. Not only did it meta lower than AC3, but I personally couldn't even force myself to finish Revelations. The setting was uninteresting, the base defense mechanic was poorly implemented, there were very few gameplay changes from the previous games (basically just the bombs and the hookblade).

The series ranking imo:

-AC2
-AC4
-AC3
-AC: Brotherhood
-AC1
-AC: Revelations

Haven't played AC Unity and AC Rogue yet, so I can't rank them. I plan to rent them both over the summer. Also haven't played AC Liberation yet even though I own it, I'll play it over the summer as well.