As always, I'll wait until the game is out and see what the perception is before making my decision on whether or not to give it a try. Assassin's Creed 3 was a huge disappointment to me overall. However, the ship missions were easily the best part of the game, and some of the most fun I had on my Xbox in all of 2012. I said at the time that if Ubisoft wanted to make a whole game focused just around that specific template, I'd lap it up.
What I meant by that statement though, was that it should be a new fucking IP! Seriously, if you don't want to continue making games based around the core experience of the original Assassin's Creed (which clearly you don't) then stop making Assassin's Creed games. We want big new IP, we crave it even, and I don't think the AAA market has ever seen a good game based entirely around pirates that I can recall, certainly not in decades. Ubisoft is one of the few publishers with the expertise and resources to really make this work on a AAA level; so please Ubi, stop trying to tie in these fresh new ideas into an old IP that they have nothing to do with, because all that happens is the impact of both the new ideas, and the core experience of the old IP, gets diluted.