Hello PaoloT,
What follows is some, but perhaps not all of the evidence, with a decision to follow.
This list assumes that VI Dimension Brass and Synchron-ized Dimension Brass are identical. If our magnanimous friends at VSL snuck in bonus patches in the conversion, those sounds might not be represented here.
Evidence
VI Horns offer both a Viennese Horn and a Triple Horn. Though Dimension Horns are playable solo, I don't recall them distinguishing per type of horn.
Dimension Horns have three variations of light dynamics not found in the VI Triple Horn.
The VI Triple Horn has three pfp variations and two strong dynamic patches, all missing in Dimension Horns.
The Viennese Horn has ten patches dedicated to dynamic no vibrato sounds. All are missing from Dimension Horns.
The Viennese Horn has recorded interval trills of a major and minor second. The Dimension Horns have no recorded trills -- only performance trills.
Dimension Trumpets have three variations of light dynamics not found in the VI Trumpet.
The VI Trumpet has two pfp variations and two strong dynamic patches, all missing in Dimension Trumpets.
The VI Trumpet has six patches dedicated to dynamic no vibrato sounds. All are missing from Dimension Trumpets.
The VI Trumpet has recorded interval trills of a major and minor second. The Dimension Trumpets have no recorded trills -- only performance trills.
Dimension Trombones have a blare sample not found in solo trombones.
Dimension Trombones have a performance trill not found in the solos.
Again, Dimension Trombones have three variations of light dynamics not found in the VI solo trombones.
VI Trombone has two strong dynamic patches not found in Dimension Trombones.
Again, there are four no vibrato dynamics for VI Trombones (normal, mute A and B) and three strong no vibrato dynamic patches in the normal VI Trombone. Dimension Trombones do not have these.
Verdict
With deep empathy for your desire to simplify your template and the frustration of so many choices, it is probably still best to keep both libraries resident.
Plowman