Honestly, I believe approach should be taken at BIAB level for building own MIDI styles from various segments that will follow chord changes...

I don't have illusions, most likely BIAB will never have support for other arranger full MIDI styles, but I do believe in-house Midi style mixer/module should happen, as there just wealth of material waiting to be discovered.

Unless of course somebody comes up with super stable VST arranger that can take Yamaha based styles. As of now, the seat is vacant.