Many years ago, my friend and colleague Bill Stanley (professor of trombone, University of Colorado at Boulder) pointed me towards an article that profoundly influenced my approach to playing, teaching, and even arranging. The Doctrine of Intent, written by Nashville Symphony principal trombonist Lawrence Borden, was a game changer for me.
Arranging with intent is critical to the quality of your chart. When you commit notes to paper, there can (and will) be mistakes. But there should be very few unintended consequences if you write with intent. This demands something deeper from the arranger than just assigning parts. It requires a sense of what each component of the music is going to sound like when played on a particular instrument, and by a human being.
There is a danger here. I will admit that, particularly early on, I wrote a lot of notes with specific people in mind. But writing something that only Matthias Hofs can make sound effortless is a recipe for disappointment. There's nothing wrong with challenging your group or a particular player, but that needs to be seasoned with discretion, especially if you want your chart to get played.
Writing with intent also means that you must consider the implications of your writing. You might be tempted to write a piece that has an epic trumpet part. Have you considered what that trumpet player is going to do for the rest of the concert? Can the arrangement be rehearsed without blowing out a lip?
In comparing my version(s) of Pictures at an Exhibition to Elgar Howarth's, a colleague publicly observed on the tuba nerd discussion list:
The Allen arrangement seems (in an attempt to make it easier for the players) to break lines and phrases up, passing them around from player to player. I think the idea was to make it less demanding on the individual players (trumpets and horns in particular). However, in rehearsal and performance it was far more difficult to put together. The lines did not flow as nicely as the Howarth.
My intent was almost correctly identified - my response to that criticism was this:
Both versions [I've done two brass versions - one for 444.12 and one for 423.11] take a more chamber music/team approach to pulling the piece off than the Howarth (IMO - but I have a horse in the race). As Sam Pilafian once quipped in this context "it's good to have friends."
As I've previously written, I think it important for every musician to be vested in the successful performance of a chart. So my intent was not about making it less demanding for a particular player (or players), but rather to even out the demand so everyone has something interesting to play. This also tends to make the writing more colorful (ever pick out a different shade of red crayon?).
Your brand as an arranger is determined by all the musicians in the band, not just the first trumpet player.