Being able to use multiple download profile (download list and resume status) with snapshot and backup and restore will be nice.
also would be nice to be able to merge profile by importing from a backup file.

Also, being able to use different properties/config profiles/presets would be nice, with export-to/import-from files.

Thanks

There is already Import/Export function available. For example you can export all settings and later selectively import them. Merging settings is possible to some point, merging transfers lists isn't.
https://support.tixati.com/settings%20-%20import%20export