I also struggle with complex song structures, especially when further developing a song from a pre-recorded jam session using the Plugin in my DAW.
For doing so I use a linear song structure without repeats.
Nevertheless it is hard to keep an overview of what to keep and what to drop and where chord changes should happen. Not to talk about the endless time consumed for re-generation and cross-checks of the changes.

If to start with some simple and easy to implement solution, the following solution would already help me a lot:

I would like to mark the background of particular areas in the chord sheet, using different colors. That should happen completely independent from the markers at the beginning of the bars.It is just meant as orientation for the target song structure. It shouldn't influence the track generation in any way.

I could then develop some overall song structure, using different colors for intended intros, verses, choruses, solo parts, bridges and endings. Afterwards I would then adjust the chords accordingly, by changing the chords, inserting and deleting bars, copying the desired chord progressions from other places etc.

I think it should be possible to add such a useful feature with little effort, as it just affects the chord sheet representation and nothing else.
The data for the "intended structure" may come from an optional add-on file stored next to the .sgu. This would ensure also compatibility with older BiaB versions, that don't know how to deal with this information.

BiaB2023 Plus, Win11, AMD 6-core, 32GByte RAM, RME Fireface UFX, Samplitude ProX7, REAPER 6, Studio ne 5, Melodyne Studio, Toontrack SD3, iZotope MP4, NI Komplete 12, Korg Collection, etc.