Most of the fans aren't exactly excited it seems (Especially around IGN, where the news is coming from) for AC:IV Black Flag.
There's not much info yet, but it doesn't promising to me. I do think Ubisoft is milking the franchise, and this usually happens after three sequels (Brotherhood). This, along with the games getting much less development time and very few new ideas could cause another COD type situation. I hope they focus on getting rid of bugs and making innovations to the plot and combat so it doesn't feel like we're playing the same game over and over.