Yeah, I get that what BIAB does is more complex but, as a practical matter, what I usually get from multiriff does not seem to contain the variety that that complexity implies! Most times, when I go through a few options, I start to get repeats pretty quickly so I think, under the hood, there may be more standardized groupings of the bits and pieces than what you describe. Maybe a better option would be for BIAB to present a set of phrases it has generated rather than the forward/back button approach. Perhaps that is what you are describing?