What I noticed and would be super cool in an classic arranger too is the fact that the chord sequence (example CM-Am-GM-GM7) is played slightly different the second time around, compared to the first time... Some elements of the orchestration seem to play kind of independently, that gives almost like random (but musicaly) choices! This variable algorithms is something I long said would be great in the styles, for avoiding the repetitive loops.
Yes you can really make those styles very dynamic, but its mostly preprogramed because the band knows what and when the next chordchange will be.. You can also tell which measures you want to act like a fill ..these fills are much better then on arrangers..
The simple reason why many of these technollogies are not on arrangers yet is that they are programmed working towards the next chordchange...
Its very different then playing with arranger styles, and takes away much of the freedom, but adds in quallity of styles and sounds...
I see it as just another tool in my setup... With all my stuff, i can play arranger styles,(tyros) preprogrammed BiaB styles, standard midi files, audio files, ableton live style, just with drums, or with several arpeggios (motif) or Karma (Kronos) or just combine them.. I love to toy around with all of these..
I gave up hope that someone will ever make a keyboard that has all of these inside