I am aware of the shortcut bar. I've had it as a button on the top since before the shortcut bar existed. Classes also has a button for the GUI switcher.
These are both side by side with the "Rocket results" button, and open a window in the same place and style as the rocket results window, so in theory, I am still following their style.
As for the shortcut bar, I have considered it, but there's 2 main issues.
1. There's a limited number of places in the shortcut bar, and if you don't have mods, the game itself will fill all those slots as you research technology. There's no room to add more and be able to show them all!
2. Most of the things on the shortcut bar have alternate means to perform that action. New blueprints for example can be grabbed from the blueprints screen, which opens by pressing B.
So, I could add it to the shortcut bar, but I wouldn't want it ONLY on the shortcut bar.