The whole series of sessions in May and October 1964 was produced by Teo Macero and sounds to me like his brainchild, his idea of an all star production. Miles' pianist and bassist, Coltrane's drummer, Getz and his new star vibist, his old buddy Brookmeyer as a leader/writer/arranger, and Bennett as vocal star with an underrepresented jazz side on his Columbia albums. Only Bennett was under contract with Columbia; Brookmeyer turned out to be a one shot deal, all the others recorded for other labels as a leader - that's the only way Macero could have 'em all.
There are some excellent solos scattered over the tracks. I wonder how the takes categorized as "no final performances" in the credits of the expanded CD reissue sound. Brookmeyer plays fine throughout, but this is not your idea of a highly charged blowing session. Leave your expectations behind, and you will probably get more out of it.
I hear no melancholy or sad strains in this music, btw.. Relaxed and elegant.
p.s. the rhythm section stirs the fire at a constant level, but does not intend to burn the forest.