Interestingly, I suggested something similar in another thread I created.
(New Naval Units [Suggestion]: Boarding Ships (II) and War Galleys (IV) )
My solution was to make a new type of ship:
Boarding Ship, to replace the Demolition Ship’s function in Feudal Age. It would attack with boarding soldiers (yellow ghost animation, the kind that come out during construction or setting up the siege) from close range to other ships. It would be weak to arrow ships (attack crew) and explosive ships.
The Dromon would then be the replacement for the Byzantine boarding ship, which attacks up close with greek fire.
That idea is also interesting and even cool.
The only downside is that the role of “Exploding” ground units that are careless enough to be near an explosive ship would be lost. That’s why I suggested the boarding ship.