I'm going to fly the flag for the X3 colour implementation and say this:
Pre X-series, I never bothered with any colour changes. It always seemed like a Madman's Breakfast thing to me; you can make anything any colour, but there's no real point to it (except of course for people with vision issues who need less or more contrast or whatever). It's more personalisation than anything else.
The X series colour stuff is built around functional purpose - what's routed where - and the UI design around that idea makes it really easy to achieve that purpose. I think it's a great bit of UI design. On the other hand, the poster boy for UI customisation, Reaper, I think has an unhinged design that's bizarrely unrelated to Getting Stuff Done. You can reskin everything, which is great fun if you're a graphic designer, but pretty much irrelevant to the business of recording and mixing.
I can sympathise though, with people perhaps wanting more control over luminosity and so on. It's not something I need, but I can see why someone would.