A few SAY they want tons on knobs and sliders on their arrangers, but usually aren't willing to pay the price all these physical controllers add to the cost. I think this is why most arranger manufacturers are hesitant to go in this direction.

For those who ARE the control freaks, if you can't afford the arrangers that DO provide these (at higher price-points), you might take a look at some of the MIDI knob and fader controllers that M-Audio, Novation, Behringer, etc., etc. all make, at very reasonable prices.

They have the advantage of being programmable, so you can set up the parameters that YOU want to control, in the layout that YOU want to see, rather than the manufacturer's idea of what you want.

They can also have the benefit (depending on arranger) of being able to control aspects of the arranger that even the factory don't allow, for instance, playing ANY fill from and to ANY variation, Break/Fill to a footswitch (many of these control surfaces have programmable pedal inputs), Talk On/Off, etc., etc..

It seems that it's mostly the tweak-heads that want this degree of power, so if your arranger doesn't provide enough control, one of these can quickly put you back in charge of your arranger, without adding a fortune to it's cost!