It feels like this issue has been brought up a dozen times already, so I am not going to repeat all the previous ideas from various threads.
Nothing has changed, Harmony is still open source and nobody considered this to be important enough to implement it so far.
(The wishlist of open issues is long, and it doesn’t even include my own most wanted wishes… except in the two initial braindump issues maybe 
)
Just a few thoughts which I had in mind for this in case anyone is interested to pick this up:
- Harmony should not censor source data, the doubtful dates should still be displayed but not seeded. Otherwise I fear that people will either think that Harmony failed to get a date or just copy the doubtful date from somewhere else.
- The current date objects could be extended with a new optional property which explains if/why a date is probably incorrect and will not be used. Maybe we even need an additional “quality” flag because dates from some providers can’t be relied on in general (like iTunes always using the original release date, which is only correct if the digital release happens to be the first release).
- Placeholder dates like January 1st should probably be auto-corrected while still being transparent about this behavior. Not sure if/how this should be combined with the new “explanation” property, maybe this should only happen at the merge stage when the placeholder date is the only remaining plausible date candidate.