User blog comment:Master Sima Yi/Assassinews 28-02-'13 — Assassin's Creed IV: Black Flag revealed/@comment-5638823-20130301131026

From the cover art I think I can tell you things about the game:

More in depth Naval, upgradeable Armour is back, tree-running on the islands, freerunning in the Towns, wildlife <-?, maybe some gameplay in London, Swords are there, 4 pistols, two hidden blades (I see identical bracers), maybe more dual weilding.