That came from a lot higher up than Matt Jeffries--the network/sponsors. They were trying to sell color TVs. Sign o' the times.The horrendous interior design?
I'd get rid of all the bright, orangey red that seemed to be used everywhere, as well as the other overly bright primaries.
And still it would be the thing I'd change given the chance. That and the uniforms.
I'm aware that the color palette was chosen to promote colour TVs, but that doesn't stop it from making my eyes bleed.
I think they called that Star Trek: The Motion Picture.