Here's a few requests I have concerning rescanning.
Others respond with other wishes.

1. Delayed rescan - the only current option is "Do it now". Two possibilities come to mind.
One, have an hour setting in the advanced configurations that would be used for "automatic rescanning" at that hour. An addtional option would perform that rescan "unattended" every day, or on selected day(s) of the week, at that hour. If the "unattended" option is not selected, clicking a button on the initial configuration application display window would cause such a rescan the next time the hour is reached.
Two, have a button on the configuration application display window allow for a rescan to be delayed by a number of hours. The user clicks the button and is prompted to enter or select a value, say between 1 and 24. The rescan would initiate when that many hours have expired.

2. Partial rescan - Create a rescan option that lets the user select only part of the configured folder tree(s) to be rescanned. If more than one folder tree is set up, the user would first select which folder tree. Then the user cold select a point in the tree to start the scan. Large libraries, or libraries with diverse collections on different drives could be refreshed faster by only selecting the part of the folder tree to be rescanned. In my case, I have 100,000+ music files and expect it to grow over time to more than 8X that. The classical library has a separate folder tree under the root for every composer with subfolders by genre and subfolders by composition within the genre. I often only work on new stuff for only one composer and genre at a time, such as Bach's Organ Works or Beethoven's Piano Sonatas. I could have 200-300 new files in that folder structure [Bach , JS/Instrumental/] to load and none elsewhere. Currently I have to wait for Asset to rescan all 100,000+ files, where I could point to just the [Bach , JS/Instrumental/] folder and reduce the rescanning to only a few thousand files.