t is subjective...some people prefer abstract while others prefer naturalistic, and others cubism, and so on.
I don't think it has as much to do about the actual work itself as it does unity and fluidity.
Meaning that all aspects of the should be represented, balanced and complete.
The splash screens should bear a simular look and feel, menus, titlebars, fonts, colors, and especially icons.
IMO the one thing that would benefit Sabayon above all others is to have a few preset themes in place that cover all the bases that users can easily switch between. The default themes that come with kde are about as inviting as an invitation to the dentist.
I don't think that there is much really new and exciting visually on the wallpaper front because as soon as someone comes out with a new or fresh approch everyone copies it until its dead in the water.
And it also has to do with what segment we want Sabayon to appeal to.
Sure someone could get all creative and do a really nice techno industrial theme that rocks every geeks world but does it appeal to a mass audience?
Research, planning, attention to details, and a few good choices are a good start.