Feedback on Export-Flag (LrC 13.3)

Great, that it is now possible to filter for exported images. But IMHO it needs some fine tuning to be useful (at least for me):

1. In the SmartCollection we have the filter "is (not) exported" – and a date needs to be provided.  Dunno for what this date is good for, if you want to filter if the image is exported at all. In the Attributes filter, the exported yes/no condition works as expected. (So, I guess, it is a mistake in the case of the SmartCollection).
2. The exported flag should be set to "not exported" when the image is re-edited: The exported flag is set if the image was exported sometime in the past. But: When you make further edits, the earlier exported image does not reflect the latest edits. So, when you make changes to the image, the exported flag should be set to "not exported".
3. The same should hold true for Vitual Copies: The state of a new virtual copy should be set to "not exported".
4. It would be helpful to save a list of filenames of the collection, e.g. for backup on CD/DVD/BD purposes.