I love the naval battles of shogun 2 and the all the ships. I have tried playing the battle of Kizugawaguchi historical battle and found the enemy O atakebune to be challenging foes and I think they would be awesome units to have in normal game-play but when I tried using them I was disappointed for two reasons. The Atakebune from Kizugawaguchi were armed with matchlocks but the normal ones were armed with bows which seriously reduces their combat effectiveness. Secondly Atakebune were meant to have iron plating on their sides which provides protection from both matchlock and fire arrows yet the in-game ones don't seem to have any armour covering making them slightly larger and tougher heavy bunes, who are still very vulnerable to fire arrows.

I think there should be a new ship which is an improved Atakebune which has both matchlock gunners making it now far deadlier to enemy ships and the sides covered with iron plating making it far more resistant to matchlocks and fire arrows than normal Atakebune but this comes at the cost of being far slower and much more expensive. The best countermeasures for Tekkousens are cannon equipped ships.