I believe most of us were hoping for a feature that would physically replace the files for an album with a new set, leaving the records unchanged. That would leave all library data intact, including play stats, cover art and playlist references.
Agreed, this is a much-desired feature, and really different from the new tag pasting capability. That's a complex process, useful in some situations (tagging a bunch of similar tracks, for instance).
But when the only need is to replace the physical media file associated with an existing database record, it should be as easy as the existing ability to replace the physical cover art file:
Select and copy the new media file then paste it to the database record (exactly how cover art can be pasted), AND/OR go to the database record, then open a dialog and select the new file to replace the old file.
This ability alone would be a HUGE help. But it would be a double huge help if MC could then recognize what is happening and offer to cross-update tags (library to file, then file back to library) to finalize the process.
The need actually applies to any type of media file -- music/audio, video, photo -- often individual files. So the process shouldn't assume there's an album involved, or be tied to track numbers or similar (though that could be an option).
