I think the majority of people don't like Luna because it's too colorful. I don't mind it myself. It's loads better than the Win95 theme.
I remember people complaining about the large fonts and the colors, when XP first came out. "It's for blind people", they said...
After a year they got used to it, and well, we all know how long XP was around for, for all the people to love (and hate).