I want to throw in one more point regarding the toughness of the defense (and the team overall, for that matter) for Canuck fans to keep in mind...
Nonis should not be building this team to compete with the Ducks, Sharks or the Flames, even if either the Ducks or Sharks win the Cup this year. The teams to be wary of over the next decade in the West are the Coyotes, Blackhawks, and to a lesser extent, the Oilers.
Yes, Vancouver needs to get tougher, but a fourth line that provides them with at least one player that can win the fights he gets into should be sufficient. It will be more important that they get tougher to play against, and that means get better in the face-off circle, improving their special teams and matching the skill level of the better teams in the conference. That means matching the skill level of the Coyotes, Hawks, Wings, Avs and Oilers rather than building a goon squad to match the Ducks, Sharks and Flames.