This could potentially be really damned awesome. I've yet to play AC3, as after hearing the reception, im waiting until i just dont have much else to play, but i did like the look of the naval ship battles and people seemed to love them, so neat. My only complaint is, well, how exactly do they plan on having assassinations? I mean, it could be really well done with moving your ship up to another ship to board it, and then fighting your way to the captain's chambers ready to cut 'em. But this is the game industry, where when something seems like it has a lot of really awesome potential, developers take it in another direction.
So we'll see. I love the AC franchise, but it's not really getting the respect from the devs that I think it deserves anymore.