You should add a feature to close all linked addons when exiting the program. And allow you to point to existing addons on disk instead of re-downloading them and losing settings (though I guess its easy enough to just copy stuff over after the installer).
https://www.reddit.com/r/pathofexile/comments/bwezvu/release_poe_addon_launcher_2_v111_start_legion_up/epxadcz/?context=3