What would be really cool is to have some e.g. ujust command, that you could quickly change different whole look and feel. Not just background wallpaper but whole designs like your desktop image. For example: ujust ubuntu-look to get something like your image above (this includes violet color, background image, icons on left…), then do ujust dinosaur-look and get something like Blufin and ujust aurora-look and you get Aurora look, ujust pinky-unicorn-look for girls, ujust fast-and-furions-look for boys to get some car theme, ujust windows-look to get Windows like look etc.
There are plenty of cool designs at Post your desktop screenshot and I think it would be fantastic to just get exactly the same look with one ujust command (or something - GUI app would be better to get preview before applying).
Usually hard core programmers and sysadmins are terrible at GUI look and design, because they spend 99% of there time in background activities. But there are some artistic users, that have great imagination… and that are the users I am looking at.