As expected, nobody cares about “reader mode”. Only once in my life has it ever come in handy…

I use this from time to time, the reader mode is an important feature to me at least and helped me making many sites readable. I think most people are happy with the mode as it is, therefore it was not high in the list for any upgrades. It's not always bad design, but just having a different taste. Lot of people like black background and white text, but to me it bleeds my eyes. If lot of people like it, that the design isn't bad.