As someone with thousands of tracks / files, I definitely suffer every time I open Jaikoz and want to read my whole library (which is actually stored in iTunes and uses the iTunes folder structure). It probably does not help that I store the library on a NAS.
Have you considered changing the way Jaikoz reads the files and tags? Perhaps breaking it up into smaller “pieces” - read 100 files at a time, return the information to the user, and then read the next 100 etc.
Also, I think it would be better to let the user start working with the application even while Jaikoz continues to read the files. This would let the user kick off doing acoustic id analysis or any other similar function.