Note: The following post is all "it seems to me that..." I am not 100% certain on the information contained in this post. I am also assuming (perhaps incorrectly?) that the problem is only the color scheme, and not the general layout.

The problem, as I understand it is that people are oversimplifying things. The more themes that are added, the harder it becomes to maintain and upgrade the forums when the time comes.

So, I think daperl has the right idea: make a white-on-black theme by just modifying the CSS of the current one. It would only be a small change in the style sheet, and would be very easy to maintain: just copy over the updated files for the black-on-white theme, and slightly tweak the CSS. The problem is that vbulletin was updated(?), so the old themes are incompatible, and it's not a simple "copy and paste".

It's very easy to sit back and complain... if you want it fixed, take some initiative, and see what you can do to help fix it.