One of the big problems with arranger play (especially now even Roland have dropped the Chord Sequencer and no-one else has one either) is......... how the hell do you use the bend lever to accurately imitate a sax (or just about any other expressive sound) when your left hand is permanently tied up playing the friggin' chords??
You either have to spend your time bouncing back and forth between playing the chords and dashing back to the bend lever (and forget about a 'scoop' or 'fall' at a chord boundary) or basically just give up on the only technique that can make a keyboard actually sound like a real horn instead of some wanky stylophone sound.
This is why I prefer to use SMFs for a lot of my performances........ I just CANNOT play a horn sound (or pedal steel or lead guitar or minimoog synth or - well, you get the picture) without using the bend lever. I am addicted to it!
And if you would all scream loud enough at your arranger's manufacturers to get the Roland Chord Sequencer idea incorporated into your keyboard, well, you would too!
BTW, I am STILL at a loss to understand why you would want to use a computer or laptop to play MIDI files into Bandstand or whatever, with ALL it's problems, when, for a fraction of the price, you can pick up a used M-GS64 or SC880Pro module and sound better and be more reliable???
The bleeding edge of technology is cool, but I wouldn't want to stake my job on it working without a single glitch. Do you.............??
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An arranger is just a tool. What matters is what you build with it..!