Railings in Revit generally need to be more user friendly. One way railings can be more user friendly is by allowing material change of balusters per railing family. Currently the baluster family itself has to be edited to change the material (i.e. if I want an aluminum 1" dia. baluster and a wooden 1" dia. baluster they have to be 2 separate families) which can really clutter the Baluster Family drop down menu. Furthermore, you can easily toggle the materiality for handrails, why not have the same for balusters?