The better your backing band, the better you play. Whether a live band, or your arranger, the same goes for both. And getting the best out of your arranger means having the most control over it.
Do you want a breakdown? Would you like the drummer to drop down to hi-hats and snare? If there's a 2/4 bar in the middle of the piece (but most are 4/4), is it easy to get to that control? Would you like hands free control of the Variations and Fills (so you can concentrate on just playing)? Is it easy to get to the Hold parameters (you just decided to medley two songs, but want the sounds to stay the same).
Maybe you are blithely oblivious to what the band is doing, Donny, but me, if I want them to do something, I'd like the tools to be able to pull it off, live.
Me... it's new styles. I don't really feel the need to change out my arranger. But new styles (and a good editing session so I can make them mine) gets my juices floating, John! 9/10 times, if you wait just a bit, conversions of the latest arranger's styles will appear for the older arrangers. Sure, they won't sound identical. But you can get them damn close!
As I've said before, most new arrangers, with new features - bet your bottom dollar that something has been taken off, moved, nerfed, made less effective. Two steps forward, one and 3/4 back! I just wish that somehow, these idiots designing these things actually KNEW what was a good feature, so they don't remove it!
Alas, I have a nasty feeling that many arranger R&D departments are run by people that would MUCH rather be playing a workstation (if they play at all!). That's about all I can come up with to explain some of the boneheaded design decisions so often made, these days...
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An arranger is just a tool. What matters is what you build with it..!