After the introduction of keywords as well as the long time available star rating I suggest that there be an option to create a SmartProject that populates itself based on defined criteria such as assigned keyword, star rating as well as combinations.
Other criterias would be welcome, but the 2 mentioned are the most basic and should be available.
The projects as of today with manually assigned content should live on.
Look at LightRooms SmartCollection for inspiration.
Regards Johannes Elkjaer Madsen
+1 from me, but I have no votes left…