I noticed this morning that a full audio system rewrite has been planned, at least since April (according to the Trello Roadmap). I recall hearing this mentioned when I asked about this issue before, but I don’t recall hearing about any progress having been made.
I’d be ecstatic to see the Audio Visualization plugin added to the list when it comes to refactoring the audio system. I realize it’s a somewhat niche feature, but there have been a good number of people making use of it over the last year that end up not being able to share their projects with anyone. As it stands now, the plugin works ok, but only inside the editor, and cannot be packaged into a standalone build. More info on that, here, in a thread I started Dec. 2014.
I understand that the audio visualization plugin was built during an Epic Friday, and as I understand it, the original developer no longer works at Epic. This must absolutely be the reason why no progress has been made here.
If Epic is rewriting the entire audio system from the ground up, I feel it’d be an extremely smart move to add FFT spectrum analysis as an inherent feature.