The real problem about the GUI (It has been said many times here) is not how the program looks, but how confusing, counterintuitve and inconsistent it is for most users, except maybe for those who have been using it for many years in a daily basis (and are simply used to its many quirks) or for those who make a really basic use of the program (just load some chords, pick an style and that's all).

The aesthetic aspect of the user interface is the simplest and most banal part of user interface design, a simple aesthetic change would have no positive effect on the user experience. Only a thorough review and redesign of the functional aspects of the GUI would contribute to improve this aspect.

Latest BIAB version, latest build.