One of the biggest things they need to change is the “Data Speed Limit” and “Data Cap” that users are able to set in the MSFS settings. The downloader & installer uses those settings and you can’t change them when updating. They need a way to bypass those settings.
So if a user set a data cap, and that cap has been reached, they won’t be able to update until their next cap cycle.
There’s a wishlist on this to have some type of override:
https://forums.flightsimulator.com/t/slow-download-of-updates-and-game-files-data-limit-override-needed/374015