I think less players will participate in the World Championships than in the World Cup. Professional players tend to take the Championships less seriously. The main attraction of the Championships is to have another outlet for playing top-end hockey even after you failed to qualify for the playoffs or after your team's been eliminated.
On top of that, the European teams loaded with NHL talent will likely all be doing well and making the playoffs, so players like Rick Nash, Joe Thornton, Martin St Louis, Vincent Lecavalier and Brad Richards won't be available. I expect the teams to be full of players who stayed at home.
From Vancouver, I'd expect Ed Jovanovski to be on the team rather easily. Bertuzzi may as well make the team if he's reinstated successfully.
But then again, for all we know, there could be an NHL season in place before the World Championships even happen.