allow dock structures to sit on retaining walls and allow for different wall materials
Docks should be buildable over a retaining wall; i.e., the outer edge of the "on-land" portion of the dock should allow for a 2-cell thickness to be taken up by a wall. This would create a similar look to modern docks and give more control over loose materials dumped into water. Given that you guys are revamping ship behaviour and dock mechanics, this would hopefully be a relatively pain-free implementation. Thematically, you're allowing for under-water construction soon so this could be a nice addition. Tier 2 walls (10-cell height?) would also work great here if ever implemented. Different materials for the walls could work here as well (i.e., start with wood, advance to reinforced concrete, etc.) with early versions being cheap but requiring maintenance (probably a different tier of maintenance or just wood).