So coastal cities in Civ 6 are pretty terrible. Water tiles give almost no yield and you can build ships from cities that are settled two tiles inland anyways. That gives you more useful production tiles and a higher chance to get a real housing boost from an aqueduct. Also those cities are not vulnerable to naval attacks. So to make coastal cities useful again I propose the following:
1. Coastal cities inherently have +1 trade routes, removed from harbours.
It gives coastal cities an immediate trade advantage, which can't be replicated by settling inland. Harbours are still useful both for coastal and non-coastal cities for different reasons. Inland cities obviously need it for building navy and coastal cities need it to boost coastal tiles and shipbuilding.
2. Lighthouse provides +1 production yield for coastal tiles. It's a pretty expensive building to build so it might as well make those coast tiles worth working on. They still won't be anywhere near overpowered because land tiles are so strong with lumbermills, farms and mines starting in the medieval era.
3. All coastal tiles get +1 food. Come on guys, if water tiles can't even provide enough food for the guys that work the tile that would be insane. There's fish everywhere in the sea, not just a few allocated tiles.
With these changes I still don't think coastal cities will be better than inland cities but it will at least make them properly viable.
1. Coastal cities inherently have +1 trade routes, removed from harbours.
It gives coastal cities an immediate trade advantage, which can't be replicated by settling inland. Harbours are still useful both for coastal and non-coastal cities for different reasons. Inland cities obviously need it for building navy and coastal cities need it to boost coastal tiles and shipbuilding.
2. Lighthouse provides +1 production yield for coastal tiles. It's a pretty expensive building to build so it might as well make those coast tiles worth working on. They still won't be anywhere near overpowered because land tiles are so strong with lumbermills, farms and mines starting in the medieval era.
3. All coastal tiles get +1 food. Come on guys, if water tiles can't even provide enough food for the guys that work the tile that would be insane. There's fish everywhere in the sea, not just a few allocated tiles.
With these changes I still don't think coastal cities will be better than inland cities but it will at least make them properly viable.