Sure thing, sorry for the delay.
Here's my idea: We have the color sliders right? For example LAB has 3 sliders with 3 bars that vary from 0 to 100.
My main idea is building 3 dials (4 in case of cmyk) or something that I could twist it and adjust the values by increments. Instead of me clicking in the color box or adjusting with mouse, I would just turn the dials with my fingers, to adjust each slider. However, since Affinity does not have an API for plugins yet, a keyboard shortcut option would suffice greatly for now. For example, I could set alt+shift+F11 to move the L slider one increment to the left, and alt+shift+F12 to the right.
Then I could set the dials to trigger these shortcuts depending on the direction they are being turned.