If you store the Import data files in main memory and encapsulate it while the map is loaded, then if a .SC2MAP file was tested it wouldn't have to save and write all the Import files every time (even if you didn't import anything to the map) to the .SC2MAP file that's about to be opened by the game. There has to be a way to skip the part of writing the unmodified imported files again to the .SC2MAP file. This would save a lot of time for developers.

Then if you had a map with a lot of imported data (music and models) and you didn't remove or import anything, saving the map would give the algorithms a much smaller input size.

So whenever you work on a map and you don't plan on importing files any time soon, you'll spend much less time waiting for the .SC2MAP to save and be opened in the game.

This would make testing a much more pleasurable experience when being able to make tiny modifications to the map and having the ability to test those minor modifications much more quickly.

It's what I like about making small maps, they save faster and they debug quicker so modifications are almost live. It's a step closer to playing and editing simultaneously.