I wish we could request External Power for the Aircraft without turning on Power in the first place.
In reality you could even give hand signals to the ground staff to connect External Power or just give them a call with your mobile phone or just call Maintenance which would make sure Airport Staff is hooking up External Power to the Aircraft.
In perticular in the Airbus its common that you enter the Flight Deck and Press the EXT PWR button when the AVAIL light is lit before even turning on the Batteries.
Here in the sim you have to turn on and drain batteries only to request a GPU via the ATC Menu.
Would be nice if you could call Ground Services (External AC Power, Air Start Unit, Fuel, Maintenance to reset failures, catering etc.) with just a cold and dark Cockpit via ATC Menu which perhaps could be renamed from ATC Menu to Communication Menu, i dont care about the name.
Or perhaps even the ATC Menu for ATC related stuff and a Submenu within the same window called Ramp Agent, Operations Agent or just Mobile Phone which can be used without any Power turned on in the aircraft.