I was thinking what if primitive gunpowder was added to the game?
It could be expensive but powerful.
We could have mining explosives, wall breaking explosives, cannons, or even gunboats.
Gunpowder has been around for some time so it may not be too far fetched.
Any ideas to further this? or is it just too unbalanced?
EDIT (To refine ideas):
Mining explosives could destroy large areas but easily cause cave-ins, kill the player, or destroy support pillars.
Wall breaking explosives would be expensive and have high prep time.
Cannons could be even more powerful that the Wall breaking explosives but are really expensive (For both ammo and cannon) as well as needing multiple people to man.
Finally, gunboats. This could be used to destroy boats and bases near the coasts. They need a lot of wood (for the main ship) and metal (for the cannon and ammo). They are have the same strength as cannons but you could blow it up if you hit the ammo racks. It can be strong but people can destroy it by: Blowing up the ammo rack(mentioned earlier) board the ship and kill the crew or sink it using you own cannon.
If something seems op or useless just reply so we could tweak the idea.