As with other areas of Unity, it seems the Keyboard Shortcut overlay (visible when holding in the super key) is not properly rendering fonts at the correct size. Please see the attached screenshot.
The numbers that appear on top applications in the unity launcher are very difficult to read because they are so small. (Launcher width is set to 36px, but even when set at the default of 48, they are still difficult to read because of how they blend with the background icons. They need to be bigger, fill up the entire area of the shaded, rounded square, and have a black outline or something to make them stick out more.
The text of the actual Keyboard Shortcuts help window is so small that I have to get very close to the screen to read it, and even then the words are not very clear at such a small size with only a 128 DPI screen. There is so much empty space on this screen, I can think of no reason not to make them all bigger to at the very least fill up the space!
Did you change manually the values of font scaling using dconf or some config tool?