It might be interesting to let docks have territory.
Superdocks already do, and it's kind of weird that regular docks don't since they're an integral part of your town. Outposts are meant to be isolated and away from your town, so it makes sense that they don't have territory.
A problem with island maps is you need space to build a civic center, and often there's not a lot of room. If docks had territory then you could build houses or towers or a barracks to get started in an area.
It would be helpful for invading on water maps, getting a foothold on your opponent's land. And yet if they capture or destroy your dock then the other buildings will be disconnected from a root territory and start blinking and decaying. Or they could deny you space to build the dock by having a civic center close enough that its territory influence covers the shoreline.
I'm not sure if it actually works, but perhaps on nomad maps players could try a dock + barracks + houses rather than a cc. Maybe "no cc" could be a variant that players agree to (like "no cav" games).
If docks are built too far into the water then the territory might not extend to the shore, which is what happened to the green player here.