Rocket production
While watching some videos on the Apollo and Artemis program, I had an idea on what if for KSA career mode, there was a system where you had to manage the manufacturing of your rockets.
It can be just as simple as making it so that it takes time to build a rocket, but further it could be you have limited production slots, first time builds taking longer (encouraging standardized rocket models), and managing construction and expansion of your space centre to scale with the space program.
More unrealistic ideas I had were managing production of individual parts like engines and probes, out-sourcing production of certain parts to contractors, and or having to deal with a scenario like current NASA with difficult small scale production because of poor management or something.
Ofc I assume there would be an amount of automation involved in some of the wilder ideas to prevent KSA from turning into a spreadsheet manager game.