Whonix doesn’t develop, software fork Tor Browser.
What Tor Browser Internal Updater does is not under control by Whonix.
This is by design.
See also:
Whonix Tor Browser Differences
Tor Browser Downloader by Whonix can do a complete re-installation.
Therefore it’s highly unlikely that any new feature will be introduced.
The hopium on the horizon to simplify the Tor Browser Update: Technical Details (which would probably also solve your request kinda since Tor Browser would be a normal Debian package) is Would stable Tor Browser deb package help or burden whonix devs?.