I think the fishing boat interaction you point out is weird and something I didn't think of. The choice right now is to improve a resource or harvest it. If this change makes a choice to not harvest it and not improve it then that's a third choice. Feels more like complexity (bad), or unintended consequences (where did my production go?) than depth but I don't think that's enough to kill the whole design. At the end of the day building a shipyard gives instant production to a coastal city now without strong adjacency, builders, Reyna, or Liang. That's a good thing. For an island city its going to be amazing to kick start that city's production.