I have no problems at all getting pretty much 100% reliability from touch screen use, Ian. As long as the GUI is designed so that the buttons are big enough and separated from each other by the required degree (which is an issue even with hardware buttons), I can hit what I need and have no worries about whether it works or not.

There is a lot of blowback from the early days of arranger (or WS) touchscreen problems, but nowadays (as the almost universal use of tablets shows) those issues are long gone.

Physical buttons add enormously to the cost of an arranger, and no redesign is possible once the production model is shipped (whereas software can be changed quite easily). I agree that the arranger's primary functions have dedicated buttons (too many people are married to that), but editing and fader control, things like that SHOULD be touchscreen, IMO.

The cost of these things is dropping like flies, and I can only hope that the day where something like an iPad screen is used for most of an arranger's functions is not too far off...