Bruno would not be a good libero as he doesn't read the game well enough and his distribution is poor.
Not saying it's the best use for them in our side, but both Kazenga and Bridcutt would be better players in that position.
Libero started as a free defender to mop up behind the central defenders. Classic example would be the Italians, such as the ultra-defensive Inter side in the 1960s.
Taking their cue from the Dutch, I think it was the West Germans in the 1970s who pioneered the attacking role that a libero...