I work a lot with Exposure adjustment and for my opinion Exposure, Offset, Gamma sliders feels very well balanced in speed when use mouse scroll. By default they adjust values by quick rough steps, and if i need more precise steps, i just press Shift key and scroll.
Same time Luminance and Contrast use totally different logic. By default they move slider to tiny steps, so i need to scroll a lot, or press complicated Command+Alt keys combo to scroll by larger steps.
So here is my suggestion:


Gamma slider may be changed to 0.05 step instead of current 0.1 step, but in all other places Gamma changes by 0.1 step, so that special 0.05 step may feels unusual.
UPDATE. Gamma slider in Optimize HDR and White Point use 0.05 step. But in Levels, Curves and Exposure it use 0.1 step. So i guess Gamma slider could be standardized everywhere to 0.05 step.
And one more idea for discussion. Don't you think that "Exposure" adjustment located in totally wrong menu group (Filter->Quality). It is simple tone curve manipulation tool, so technically belongs to same main group as Curves and Levels.