The ability to add whatever settings you want from the main settings page into the quick settings page on the right hand side of your browser.
Example: I switch hardware accel on and off for certain things and it causes issues for me with it on, but i need it on for some things, so the ability to quickly toggle it, restart my browser and continue on what I'm doing would be great.
Or the ability to access your passwords menu from the quick settings tab would also be great.