Could you add an option to the range check module to fade out the opacity of the bars instead of darkening them?
I find that a much more intuitive way to recognize someone is out of my range than the bar being a darker shade (plus my unit frames addon does that with friendly players already).
It's only really necessary in 5s where you lose track of enemies in the mess, but it'd be a great help.

I used Shadowed Unit Frames or BlizzardRaidFrames as a reference, as it is very popular and does this with darkening as well.

I can add an option.