And who's to say they won't squeeze in naval combat in some of that?
Well, Paradox is notoriously bad at naval combat, and I think it would require completely re-balancing the game (I can imagine all the threads complaining that the uber-Fatimid fleet keeps wiping out every incoming Crusade before it even gets there). I don't even think it was really historically important in this era, besides mostly blockades and sieges of cities which incorporated fleets.