I always wanted to do three things in the original AI war. One of which is distance measuring -- which I really hope exists when I sneak a (blind) Armored Warhead deep into space into AI Homeworld and blitz-destroy that Wrath Lance, while racing the shot of Warhead Interceptor. Currently I do that with the time machine -- a.k.a Save/Load.
The second thing is copying/rotating entire defense setups, or even better, with some simpler ways to draw lines between important objects, like wormholes. You see, most of the time, other than the most unusual cases(like hubs with 8 connections), planetary defenses are basically in the same form(Kahuna-style, pointed spear of death, road of mines, etc). And currently I think it is somewhat tedious to setup everything with line-drawing with movements, multi line placements, etc.
The third thing is the ability to really disable defense while shutting down power, but I might be using the wrong wording here. Some may say this poses balance issues because then you can builld defenses on everywhere and turn on as needed, but I don't mean that. Time by time, the main chokepoint gets breached, with three quarters of turrents still remaining but command station and energy collector gone -- And you are in total blackout. In the Classic, I have no choice but scrap all turrets and rebuild them from scrach later. That is super tedious -- I would hope there is an option to turn off or at least scrap with remainings, so that I don't need to place the turrets again. Especially if the chokepoint features careful/delicate/ingenious timing optimization which will drop performance by a few times with the slightest modification(I have a test on defending a 10/10 CPA with 10000+ ships with only one world worth of energy and K. Moving the configuration slightly, or on another map with different wormhold position, will spell doom less than half way through).