It does seem like while this may be an interesting game on its own (open-world pirate game!), it only seems to have the Assassin's Creed name for marketing purposes. The AC series has always been less about really being an stealthy assassin as many would have hoped, but this may be stretching a bit too far?
It's definitely a game I'm looking forward to, if they improve on what they did good in AC3 and remove the lesser ideas and the setting should be interesting. As far as the series is concerned, though, it looks to be kind of a mess. And this yearly nonsense is oversaturating even me, who has gotten every AC game pretty much at launch.