The text we use is simple text with only single fonts and homogounous properties. We have to render on many different platforms, and even though is seems quite simple, just supporting superscript and subscript would make the text editor and rendering about
10 times more code.
You can however, make very fancy text and import it as a Image with transparent background. Saving to a PNG with transparencey you can have any effect you want and we will scale the image to the screen size of the user.