Interesting topic! Most know I have a love-hate relationship with arrangers, but the bottom line is, arrangers have kept me working in a very competitive and price snsitive environment.
I approach it like this: I work with a live jazz trio...no arranger. Then, I work with a core of excellent sidemen, including a guitarist, flugelhorn player, saxophone/flute player, percussionists, several singers, etc.on other jobs. Bass players and trap drummers are generally pretty rough with an arranger.
This works fine for me. I choose the appropriate sidemen according to the kind of job. I even add sidemen when it is not really required, depending on the type of job, budget and my level of boredom in doing a single. The bottom line is, for me, music is meant to be played wih other musicians. But, times are different...the only society big band in the area only works six or seven times a year.
Another advantage of using an arranger is I control the performance. If someone is difficult or unhappy...drunk or whatever, I can send thim home and complete the job.
Arrangers are great tools. It's just that, sometimes I miss the interaction...the great unspoken communication that permits alterating arrangements on the fly, playing off other players, etc.
Russ