About booleans vs other types, what about:
Colors:
- booleans (just ON/OFF): use green LEDs
- integer: use blue indicators
Shapes:
- booleans: use round LEDs (green, of course)
- values in some min-max range (with some size-like meaning, e.g. audio gain, ISO, WB): use meters. Optional OFF position (the meter gets dimmed if the feature can be considered inactive, like WBShift 0 or bitrate 1.0x). Meters are blue.
- discrete choices (without any size meaning; show choice X out of N) - e.g. picture style, focus peaking algorithm: maybe a spin indicator (now looks like a pizza slice, before it looked like dice). Also blue. Better idea for this?

