I'm not convinced Nonu or SBW would cover wing/fullback well enough for people to feel he is a bench option. For me it has to be one or the other in the team at one point. Neither Williams or Nonu are quick enough to be effective there or have had enough time to become confident under the high ball. I know Nonu used to cover wing for the Hurricanes but that was almost four years ago, and it wasn't his best position even then. It sucks that one would miss out on the odd match, but it's better than putting them in a position in which they are not world class and would be a liability, in place of players who are experienced there.