If they wanted the top row to be flexible, I would have prefered individual keys with an eink-style surface that could change, but would look completely normal otherwise.
The bar would be perfect for adjusting volume and brightness if Apple decided to remove the awful indicator pop-up in the monitor.
Currently I can adjust my volume with my eyes closed in bed at night when listening to a podcast because it's the second key from the top right of the keyboard.
I generally despise button controls for things that could be continuous. I hated it when they replaced the volume control in many car radios (http://media.gettyimages.com/photos/radio-volume-picture-id1...).