Just an fyi to anyone making or thinking of making one of these: Turning a knob with a mouse is the worst interface I can think of. I don't know why audio apps/DAWs fall so hard on skeuomorphism here when the interface just doesn't make sense in the context.
A slick-looking GUI is a kind of ad for the app. As author of an accessible, terminal-based DAW app, I contrast remembering an incantation like 'add-track' or 'list-buses' with hunting around. These incantations can have shorter abbreviations, such 'lb' for list buses, and 'help bus' or 'h bus' to be sufficiently discoverable, easier for both implementer and user. And then to have hotkeys to bump plugin parameters +/- 1/10/100 etc. Probably I'm pissing into the wind to think the majority of users will ever choose this -- and GUIs do provide amazing facilities for many purposes -- but we do have a huge array of choices on linux, including this plethora of music creation and production apps. That is a big success, IMO.