So, there is my idea : Why do not ask canonical to do a poll for all the community to vote for that theme we want for Ibex?
For exemple, vote for a specific icon, metacity or gdm theme. Or vote for specifics colors. So, if canonical do a poll, we will see wath the community want, and the new theme will be better!
I think they're very aware of the brand identity issue and it's strongly linked with warm / brown colors. What I think would be best is to default to whatever the Ubuntu default has to be and have themes available in all sorts of other colors. A lot of people like blue for instance, there should be a blue theme. I like orange and grey but not brown....