Why didnt they ever show the inside of a City Destroyer at all?

The most that they did was show the bridge where David found the distress signal onboard the City Destroyer that landed in Umbutu, but they dont show what the inside of the ship looks like, or any maps of it that show what the different parts of the ship do or anything, they didnt even release any official guide showing the characters and ships and aliens either, would have been much better, Star Trek and Star Wars have guide books with blueprints for the ships after all.

Maybe the Sphere can teach them how to turn the City Destroyer back on and they can use it to fly to the Refugee planet and fight the Hive Aliens, basically use the intact ship against its own builders, and download their technology from it.