BIAB is amazing, and many of its subtleties have to do with the same fine tuning that can be done differently in RB. Since I prefer fine-tuning in RB, I find that I use BIAB mostly to generate my chords in a particular style.

In other words, I enter my chords, pick a style and hit PLAY/GEN and the whole song gets built

How much trouble would it be to add that capability to RB?