I believe making an arranger out of plugin or BIAB is theoretically possible, but styles would have to tailored specifically for use with such arranger. Unlike a fairly straight forward MIDI arrangers, BIAB uses randomization algorithm making use of different takes over same chords. You DON'T want an arranger that would play something different from what you've last heard. If you make automatic STRICT rule of selection, it might not necessarily use the best take, but take worst. So I think to make something decent, each individual style would have to go through a very in depth section curation specifically designed for arranger.

Arranger is potentially a very promising direction, but for now I wish PGM would just fix what needs to be fixed and finish half baked items that need to be finished in BIAB & Plugin. Especially focusing on VST3 implementation that supposedly coming later this year and its MIDI routing to other tracks via simple method, not with some complex 10 step workaround.

For now, I am very glad they figured out use multicore processing for generating/regenerating tracks. That was a very pleasant surprise for 2024. Saves a lot of time.