To me it looks like the bigger problem is the lack of decent GTK controls for multimedia/music production. A lot of Linux/FOSS software suffers from that limita

To me it looks like the bigger problem is the lack of decent GTK controls for multimedia/music production. A lot of Linux/FOSS software suffers from that limitation, Audacity being just one of them. To be honest, most Windows based plugins also historically came with their own interface because the stock UI wasn't good/fast/pretty enough for some uses (knobs, waveform display and manipulation, etc) although I believe today it shouldn't be too hard to start the development of a FOSS generic multiplatform widgets kit that doesn't suck for that purpose.