I am rather against making a new theme - we are already stretched thin with keeping packages maintained, the artwork team is in the same boat. i feel that it would be far more prudent to start by making a new set of icons and a colour scheme, maybe changing a few bits of the default set up to make the look more unique, but keeping oxygen as the default across the whole distro - I have not heard anything negative about this so it would seem that it is/was a good choice.
If there are enough people who can focus on improving cosmetic things, then they would probably be better to work on some of the existing artwork bugs, such as the code that sets the default background resolution.
