Like many data recovery tools, Recuva focuses on deleted and lost files - but there's also a need to recover existing files in certain contexts, where two things will help:
1) Hide deleted files
Just as you can show only deleted while hiding existing, the reverse is useful; show only existing, not deleted (or lost), to de-clutter the view.
2) Sanity-check existing files
This is harder work, but would be useful; just as deleted files are rated on quality (e.g. whether overwritten or not), so one could check integrity of existing files...
2.2) Correct header bytes for known-content types, similar to how lost files are detected
It can be very helpful to see a report like...
X files of total Y bytes
X files of Y bytes (%) cross-linked
X files of Y bytes (%) type-invalid
...to assess e.g. whether re-calculated partitions and file system alignment etc. are correct or not.