Been thinking of this idea for just a day, so by all means put it through the blender, give it a throw, and let me know if you don't think it'll stick.
I feel like this game could have more dynamics added to it if we had more than (and definetley at this stage in the development in AH (with so much non-aircraft aditions)) one V-base and one Port modeled on the default maps.
With vehicles I'm thinking of two categories of fields (similar to how airfields come in small, medium and large varieties): One would be large depots, something that could feature more targets of opportunity for aircraft or large organised efforts (everything from tracks with trains to a small runways with one ac hangar and a few fighters available). These would be something difficult for less than 3/4 players to knock out in heavy fighters. The second would be like current V-bases, maybe 1/2 the structures and 70-80% the AAA, and something a couple of aircraft and/or vehicles could handle capturing or shutting down (a smaller, but not solo effort). The benefit of them being smaller oc is that they could be used more prolificly, say at current tank towns or to make multiple minerature tank towns.
Ports: some maps only have 2-3 ports at most per country, and the current 1-port model is fine on those maps. But on other maps, each country maybe has 12-ports and CV fleets. Currently some ports can be expanded by placing and linking an airfield to them, but they're essentialy airfield, with the same port modeled nearby. My idea is if the port itself came in 2 or 3 different varieties, improvements can be made for the game and gameplay in the MAs. One being a small and simple basic port (IE the current model). Predicting that someday (ie: 2-3 years) float planes or more patrol boats will come into AH, maybe these bases could play home to these craft and be placed more prolificly and evenly scattered across a map. And then to compliment these ports would be much larger ports, where perhaps an airfield could be incorporated into the model, but where some new concepts could be toyed with too: some serious sea convoys (something more than one tug and a handful of barges) with no CVs in them, and that travel a longer distance than your current resuply convoys... that's one idea that can be toyed with them. Another is adding a variety of ports could add more variety of task groups to the game that can spawn at them - imagine the change in dynamic if more thought than sending a small-CV group to a large-port was required, because if that small-cv group runs into the large-cv group based there, it will likely get easily creamed...
Anyways, fire away. The wish is to drasticly change just the single-port and single-GV base cookie cutter we see stamped all over the MAs, and not really overshadow the air aspect by doing so (but while obviously catering to all players - air, sea or ground with the changes - and not just one).