I like to have an adjustment, that gives me in the year column the earliest release date of the song and this should be independent of the Release Type. (normally the earliest release date of a song, is the release date of the single, then album and if there is any single or album, the first release date of a compilation)
Maybe like lyrics but here: Action -> earliest release date
or as an adjustment in the Preference, that would be better 
Paul, what’s the price?
I guess there is a difference but how does this differ from Preferences/Match/Earliest Release Date in your opinion?
If you select this option releases with an earlier release date will get a score boost, of course if you have two releases and release a is a later release date but matches your songs better you will probably get the later release, but would you want it any other way ?
At the moment on Musicbrainz they have release , with release events but when NGS is released all release events will be separate releases, I think this will be better for you.
With the Prefer not Compilations options you can now ensure you match to an original release, (be it album or single) if it exists in the database.
but if I have a compilation album in my collection - say Greatest Hits - I like to keep the name of the album, but not the compilation-year of the album.
Right understand.
So to do this we would need to find all instances of this track, and take the release date of the earliest release, I think it would also be useful to give you to option to write this date to an Original Release Time field instead of year field, this field exists in the ID3 tab but not he general tab at the moment.
With the current Musicbrainz Database this is difficult because every track exists only once on an album. The only track<->track path is via the puid because hopefully most of the tracks should have a shared puid, but of course many tracks do not have a puid. Additionally we have to to do a lookup for each puid, and then a release lookup to get the date so this could be very slow.
However in Musicbrainz NGS tracks now exist in multiple albums, so it is easier and quicker to find all the releases a track has appeared on. So I’ll commit to do this but not until Musicbrainz NGS is released which should be within a couple of months.
If a few of you are interested in this a combined payment of �100 would secure this for the first release post NGS, but best to wait for a definite release date of NGS before sending any money.