It would be useful to improve the import of sessions into a catalog by ensuring that the session and the catalog synchronize with each other. That is, once a session has been imported into the catalog, if one were to make further changes to a photo in the catalog or in the session, the same change would be reflected and aligned in both parts of the catalog and in the session.
Came here to post exactly this.
I would love to have a master catalog that contains imported sessions, but the sessions and photos in them remain "Live" in their current locations, and if changes are made at the catalog level they are ported down into the sessions.
The point being if I want to find all images of an image tagged "Lion", I can use the master catalog which will search across all sessions that were imported, but I can still easily work within one session & enjoy the benefits of the isolated session workflow.
However if I want to just work on one shoot, I can work within that individual session, OR when I make edits from the master catalog, they are transposed into the respective session.
Because I shoot session based on location, I do not use the catalog features at all, and lose "Cross Session" searching abilities which is a shame. Importing everything into a single catalog just isn't feasible due to volume.