If Backstrom and Semin play like crap like they did in the playoffs , they won't go past the second round again next season. They didn't have a bad goalie this year , Neuvirth was solid most of the time. So although I must admit Vokoun is an improvement for them , it's not that big of an improvement over Neuvirth.
Vokoun is an astronomical improvement over Neuvirth/Varlamov/Holtby. A three-man goaltending rotation pretty much means you have no goaltender, which was the case last season. The trifecta in Washington may have had good stats, but I think we all know that they were pretty lacklustre goaltenders. The additions of Vokoun, Joel Ward, and Roman Hamrlik give this team something they've never had: guys who can and have performed up to or greater than their talent levels on the big stage. Their team is a whole new animal now, in my opinion. I think they actually have a chance to make the Cup with this team, and I would've never said that beforehand.
However, their big stars like Semin, Backstrom, and Ovechkin will have to do what they've never done before and deliver in the playoffs, so I'm still not betting on this team.