Who is to say Zambrotta is right footed? When he played on the right, he would cut in and take many shots with his left foot. He is able to do the same playing on the left so in my books, Zambro has no opposite foot.
i think it all depends on the formation. If the team needs a player who can defend and attack well and take the whole left wing, then zambro must be that player. This of course would mean a player like Mutu playing more central behind the forwards and camoranesi taking the right wing.
But if this isnt the case, then i dont see a problem having them play on either side.