This is probably quite the stretch goal, but I couldn't find any existing suggestions already

The goal of this wizard would be to:

• help/guide the user to the optimal workflow to match releases, so basically the step from a cluster to a fully matched release or from loading a previously saved release
• provide an optimized UX / popup window explicitly for this workflow
• reduce as much click and scroll requirements as possible (maybe even support a keyboard only interface using shortcuts). When processing a large collection the current UI is just very RSI-inducing unfortunately
• reduce potential eye-strain
• provide high quality feedback & suggestions
• the current main window would then be mainly about providing a flexible & global overview about your collection (progress)

A shortlist of potential features/workflow:

• User adds files and clusters them
  • adding files and clustering them would explicitly not be part of the wizard, the current UI is already really good at that and not including that in the wizard keeps the wizard optimized for the match release workflow
• User starts wizard (with or without a cluster selected)
  • If no cluster selected, wizard selects the first cluster from the list
  • Wizard has prev/next options to skip a cluster and proceed to another cluster
• Wizard loads the best matched release for the selected cluster
• Wizard provides an optimized search interface for releases that doesn't require the user to understand the advanced query syntax
  • f.e. it has separate text fields for album and artist
  • by default searching happens using AND conditions, i.e. when searching for artist "the prodigy" and album firestarter then it does not return any results of artists that do not match "the prodigy". Currently when searching for `artist:"the prodigy" firestarter` the search also returns results for many other artists which clutters the overview. You have to search on `artist:"the prodigy" AND firestarter` to really only show results from the prodigy.
  • provide an interface to quickly search by track title and/or title (currently you can only search on albums, but it would be helpful if you could search for albums where track 12 on cd 2 matches a word
• It shows all tracks and their match status
  • User can fully change the release and it's tracks, the Wizard keeps track if there are any changes and provide the user with an option to either update the existing release (not sure about this), submit a new release or only keep the changes to the release local (see PICARD-2978)
• Wizard shows a list of all available clusters, ordered by highest probability to be related to the current cluster
  • This is helpful in cases where Picard made two separate clusters for a release, f.e. because files are tagged with `Album cd1` and `Album cd2` which Picard atm does not combine into a single cluster
  • match clusters by f.e. text distance between artist & album name
• Wizard also shows a list of all available unclustered files, ordered by highest probability to be related to the current cluster
  • This is helpful for missing tracks and/or for cases when you perfectly matched a release but also still have an additional bonus track as unclustered file
  • it matches probability both by filename as tag (for artist / album / track title / duration)
  • the only difference with the current unclustered file list is that it's ordered by probability of being related. The user should still be able to see all unclustered files in the wizard
  • user can quick search/filter the unclustered files by tag and/or file name
• Files can be removed / moved to trash from within the wizard
• Wizard clearly indicates the match status of the release

Note that I did not make statements about how the UI should look like, it could be split panes, tabs etc. That would be for a potential next step