People have been saying that for 2 years. "The next version" is always when they'll dump the sordid brown.
Really, geeks and marketers can't be wrong about what normal people like, except when that contradicts with what normal people say they like :)
I actually tried to organize a theme contest in conjuction with DeviantArt for 8.04, working with Ubuntu Artwork team, with prizes etc.
The first thing that happened was that winners were limited to working with the existing palette. The directive comes from Mark Shuttleworth and Ubuntu art are powerless to change it. The contest didn't go ahead.
However Mark seems to have recently changed his mind.