Ah, my little grasshopper, please pay attention.
The visual usability of GUI is affected by several factors:
- The screen: the new theme colors are almost unbearable in my desktop (big high luminance and high resolution screen) while much easier in the n810. Screen resolution and size affect the available space and layout.
- The system fonts: bolder fonts make orange and gray text more readable, since the contrast is increased. On the other hand, the need of bigger fonts in the small screen causes the "right bar on top" problem.
- The room illumination: the screen background must not have excessive contrast with the room background. The eye can't be adapted to dark and light at the same time.
- And,most important, the eye of the beholder, and, you see, it is not a question of beauty, but there are such thing as old people, color blindness, macular degeneration, and many other eye diseases, so what may appear fine to you, might be unbearable to other people.

And that is why "one size fits all" is so a bad idea, and the first rule of ergonomics/usability is to allow the system to be adjusted to the user needs and not the other way around.

So, my little grasshopper, this is why so much people ask for a choice.