I know it's been suggested before, but with the increasing use of NOE with overwhelming #'s of aircraft, perhaps it's time to modify base defenses.
The defenses would be upgraded a bit against air, sea, and land attack via a two fold method.
First, add either German 88mm cannon, useful as manable AA or able to be depressed and used as antitank/GV defense weapons. Alternative choice, and the one I would prefer, would be the US 90mm M2, also able to alternate between AA and ground defense. The M2 would have the capability of proximity fusing, much like the USN 5 inchers, OR the user could select the fuse timing (perhaps by a ".r 50 command to set the fuse for 5K range? Use 30, 35, 40, etc to set the fusing for 3.0, 3.5, and 4.0K ranges). For ground defense, use the backspace key just as on a ship to select between AA and AP round. Either 88mm or 90mm weapons could be sited as batteries of 4 guns, as in RL, or as individual guns arrayed in and around the base and just as importantly, in the town. All these guns would have a 360 degree field of fire, just as the mannable guns do now.
Second, after looking at the various ports and sea side airbases, a lot of them have the shore batteries sited with fields of fire that do not protect the base and town. My proposal would be to have a minimum of two SB's at any base situated along the shore, with at least one of them having a field of fire that will protect the town and shoreline in front of it. Bases having 4 SB's would have two inner SB's sited for fields of fire to cover the base and town, and two outer SB's sited to have fields of fire that only cover sea lanes.
Third, have one battery of 88/90mm guns sited up on the "pyramid" with the SB's, also with the ability to depress to engage ground targets.
That's my proposal, some will hate it, some will look at this wall o text and go

and hopefully some of you will agree.
Just my thoughts on how to improve the game.
<S>!!