It is cool and damp here in Colorado this morning - it feels like fall. The sound of (gulp) drum lines fills the air.
My high school band director is widely regarded as one of the best to have ever walked the face of the planet. Larry Wallace had a Symphonic Band, a Symphony Winds, an Orchestra and a couple of jazz bands in his program. We did have a marching band, but the band learned its show during a relatively short camp in the days prior to the start of class - we spent zero time on marching band once classes started other than to (grudgingly) show up at football games. Once the school year began, curriculum took over and the bands sat down and started rehearsing the first concerts of the school year. He regularly encouraged chamber music, and it was rare to walk into building in the morning and not hear great music blaring from the high end audio system in the band room.
Wallace also nearly insisted that his band kids take music history and music theory, especially those he thought would go on in music at the college level. After my first year in high school, he handed me his personal copy of Grout History of Western Music and told me in no uncertain terms to read it over the summer. Which I did. Now, 40 years later, that exact book sits next to my desk like a talisman. Wallace taught a rigorous HS theory curriculum that incorporated sight singing and melodic/harmonic dictation with written theory, and would put most undergraduate theory curriculum to shame.
I've buried the lead, so to speak.
What's often lost in dictation, sight singing, chord voicing, and 4 part writing is perhaps the most important lesson of all - VOICE LEADING. Bach's chorale writing is studied in theory courses because he was a master craftsman - the 'rules' for voicing chords are a byproduct of Bach's uncanny ability to write a melodic line in every voice. Bach was not an exceptional melodist, though he wrote some memorable ones; but he was an expert and detail oriented craftsman.
I've played a lot of compositions and arrangements in my 35+ years as a pro. The things that stand out the most - parts that are written idiomatically for the instruments (this is a topic for another day), and voices in the individual parts that lead well. Played musically, Come to Jesus in whole notes can sound like a good chart if the voice leading is tidy. The inverse is also true - sadly all too often.
Brass instruments are poorly suited to jumping around a lot, and yet young arrangers (and some more experienced) will write a note just about anywhere if it fills out their vertical harmony needs. If your voices are jumping around a lot, there is almost certainly a better way to write it.
Good solid chord voicing and voice leading are not just theoretical concepts.