Bachus, here are my thoughts, based mostly on observations from this board. They may also only apply to American users.

Arranger users tend to be older than your average synth/WS user and therefore less 'geeky'. They are willing to pay top dollar and therefore want everything to sound great OOTB and with one button push. As a group, they are least likely to delve into the heart of the OS, explore and employ all the features of a machine, embrace new but COMPLEX technology, utilize available software add-ons. I don't think we get less creative as we get older, I just think we get lazier. Of course there are always exceptions (Diki, Rikki) and people like Gary who will thoroughly investigate every operational possibility, but by and large, most arranger players just want to play; and play as simply as possible. If you look at their 'most wanted' features, they will likely be built-in MP3 players, sequencers, harmonizers, etc. All available and accessible with one or two button pushes. Yamaha's drum graphics painted on the outside of the case is a clear indicator of their perception of the need to 'dumb down' the operation of even their high-end products.

Everything you propose and all other approaches (ie. Liontracs) that involve (visible) software interaction, would, IMO, have to be made so transparent and so intuitive that it stayed within the boundaries of current OS's (in terms of simplicity and ease of use). And that would be difficult.

Processes and features such as the ones you describe, will only be implemented when and if younger and more tech-oriented users migrate towards arranger keyboards. Again, JMO.

chas