With Track IDs expected to be brought in in May, Recordings being defined as mixes in a series of meetings in January, and some subsequent discussion relating to what exactly a mix is, I've produced a proposal for a new guideline that treats recordings as mixes.

The guideline can be viewed here:

https://wiki.musicbrainz.org/User:LordSputnik/Proposals/Style/Recording

This updated guideline should allow editors a lot more freedom in merging recordings. For a start, there is no longer any requirement for recordings to be split based on "unique" or "distinct" audio.

When reading the proposed guideline, the following page should be used as a reference:

https://wiki.musicbrainz.org/User:LordSputnik/Proposals/Recording

This second page isn't part of the proposal, and may eventually be used to update the Recording definition page, but that's completely up to the developers.