The MK2 parts are in like 50 shades of gray/white! They don't all match!

[HafCoJoe]

I was building a stereotypical plane with the Mk2 parts and I found this:

The colors don't all match. The MK2 crew cabin (the part right behind the Mk2 cockpit) is less dirty than the other Mk2 parts and it doesn't match well with them. Same with the long Mk2 oxidizer fuel tank. Please don't let this fall into the procrastination bucket like some IVA views have and fix it!

[EdFred]

They match by Kerbal standards.

[nli2work]

some parts are more popular than others

[HafCoJoe]

some parts are more popular than others

"All Boostahs are equal, though some are more equal than others" - Kerbal Farm

As to matching by Kerbal standards I'd say that's an invalid point. The parts are meant to match in the basic of color coding. Maybe not squeaky clean but at least matching color wise.