It sure looks as though there will be a fair amount of naval combat and/or exploration, a likely mechanical holdover from the well-received Assassin's Creed IV: Black Flag. Now, that's not to say that we'll see pirate ships and have the same feel as the action in Black Flag, but we will likely have some sort of action on the seas in the new game.
The current rumor is that along with the rivers and byways, the game map will be so large that the Mediterranean Sea is included as players can travel from Egypt to Greece. The inclusion of naval play can only make the world of the Assassins feel that much larger as we'll likely run into Persians and Macedonians if the gameplay era is correct.
