...Out of the ~400 billion systems available. I don't see a problem here, there are plenty of systems for fleet cancer to park in where I won't have to deal with themThere is somewhere on the order of 12,000 fleet carriers in the game so your limit would require they be spread over 36,000 systems.
Where they wouldn't nerf game performance, foul up navigation, or clutter the system map to a ludicrous degree. Because RL != game.You could place 1,000 fleet carriers in orbit around the earth and you still wouldn't be able to see one from another.
Also, your elementary math is fail.