The export dialog in TWX should allow for multi-project selection, not just single selection. Especially with the "building block" concept, you normally would have to export more than one project. This is currently very tedious and error-prone, as you have to to open the export dialog and configure it for each project.
Also, all exports are named "Entities.xml" and you'd have to do renaming as well.
If there was a multi-selection, you'd only have to run ONE export. Each project would get it's own XML file named <project>-Entities.xml. This could be done with multi-download issued by the server or simply by zipping them together and delivering the zip file.