I think it would be awesome to have several mouse scroll-wheel type wheels in a row, instead of knobs.
Personally I want to test making a keyboard like this, with a columnar layout (along the lines of Maltron or Ergodox) and on one hand, instead of the number row, put a row of scroll wheels, one above each finger column (probably about 3 of these is plenty sufficient) so that they’re extremely easy to reach without moving the hand. A combination of holding a modifier key (or chord) using the other hand – or perhaps pressing a shortcut first with the same hand if the other hand is on the mouse – plus spinning these knobs, would adjust some parameter in an audio/graphics/video/whatever app (or adjust the volume or brightness, rotate through tabs/windows/apps, scroll or zoom a document, etc.).
[By the way, I think Adobe Lightroom (or to be more precise Adobe Camera RAW) has the laziest user interface designers of any app outside of Microsoft. A giant list of sliders is literally the most trivial and thoughtless UI you could make for anything, and basically shows no consideration of what the user actually wants to do or what relationships are involved in the mental/mathematical models the software is built on. This is what you get when the users, the academic scientists coming up with the models, the engineers implementing the software, and the user interface designers don’t actually understand all the parts of the problem at once, don’t really talk to each-other, and take everything else outside their own narrow roles for granted.]