Some of the current structures that we’ve been seeing from the sneak peeks are mostly constructional/terraforming, with a few building options for defense. While they might already be planned and just not shown yet, I think adding special structures would be interesting and also give builders another use other than for ship parts.
The idea is to add similar parts to ship parts that can be colored and upgraded/enchanted, and are available in their respective tabs similar to ship parts. These could be defensive weapons like cannons, trebuchets, ballistas, and special wall or structure types. There could also be special structure parts like Ravenna Castello walls, roofs, stairs, etc, specifically found in the Ravenna region. When any special item is broken (specifically things like cannons, not structural parts) they could enter a “broken” state and re-enter your inventory, which requires returning to a builder to have it fixed, which may cost more than it initially took to build. You could also have banners/flags that, instead of displaying your clan logo, display a ship sail pattern with a custom color.
Part of the reason why I think this would be a good idea to add is because 1: It already technically exists in the game (Fort Talos), 2: It would make it easier to fight players controlling ships while on land. 3: It adds more depth to the building system and requires players to explore more before instantly creating a base that is just a 6 layered circle of walls. I also feel its too easy to just make an entire base when everything is readily made available to you if you have alot of galleons, which in this state of the game, are very easy to farm. Finally, it can give builders a thing to sell other than ship parts.
