In the Nodoka Metacity theme the window title and button foreground color is always white, regardless of the highlighted element foreground color setting. This results in unreadable window title with light highlight colors.
Well, as the fix was quite easy and I had some time, I decided to fix it right now. I've just commited the needed changes to git. It makes use of gtk:fg[SELECTED] to colourize the buttons and the title.
I've tested it with a few fg[SELECTED] colour settings and high-contrast Inverse GTK theme, and it seems to work so closing as FIXED.