Thank you for contacting Sitefinity support and for your suggestion.
I filed a feature request which you can follow as PITS Issue by its ID: 7445.
Here you can find this PITS Issue: Public URL
As a workaround I would like to remind you that you can copy the SQL database and website folder so you efectively clone the website and on the cloned website delete what you don want there. This workaround is usefull in the case where you want to export and import big part of a particular site.
the Telerik team
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