personally i believe that the city should be linked to support zone strats like we had as a supply chain. production starts at the cities, goes to the strats, then to the bases.
take out the strats and time goes up, take out the cities and time goes up and take out both and time goes to maximum downtime.
have capturable zones back also if we could. add a major bonus for taking out the cities and HQ and you have a major working supply and strategic setup again <S>