This is probably equal parts generation gap, regional culture, and just aesthetics between the two of us, but here in western PA, and where I've lived in Hawaii, Massachusetts, Michigan, and the Bay Area, the word "underground" never drew any negative connotation, in the last 10 years as a carpenter talking with people about alternative buildings. So I must just have missed that boat. No resistance to the word has ever come up. I've seen the problems of underground houses decried in many books, but not the way you presented it!
I enjoyed your very nice article, and I'll take some lessons from it, but I'll just keep calling it an "underground" house! The "Wheaton" earth-sheltering method. I don't plan to ever say "wofati" but if I run into someone who does, I'll let you know that it's catching on!
Also, "Wo Fat" was apparently a villain from Hawaii Five-O. (Never watched it.)