Sunny wrote something in his post that might seem a bit confusing:
"No one has conclusively shown a meaningful difference in skill between NHL goaltenders. I’m not saying it doesn’t exist, I’m just saying no one’s really proved it, and that all signs point to goaltending differences being far less important than everyone thinks."
Sunny's claim is that differences in talent are far smaller than people think. And indeed they are - if you signed Tomas Vokoun to a long-term contract, you got a great deal on a superstar goalie, but his true talent is still only about 5.5 wins per season better than that of the 30th-best regular goaltender (Ray Emery at the moment...) However, goaltenders can clearly exceed their talent levels, which gives you seasons like Ryan Miller's 2009-10, which may be worth 9-10 wins.
As I showed before, there's no good reason to expect a season-long hot streak to continue into the playoffs, so the difference between goaltenders is closer to their long-term averages. If a team went from a scrap-heap goaltender to Vokoun in net, they'd go from 40/60 underdogs to 60/40 favorites - but in a playoff series, the difference between the best goalie (Halak? Luongo? Brodeur? Anderson? Miller?) to the worst is smaller than during the regular season. Being favored 55% instead of being a 45% underdog is a big deal, but it's not a four-game sweep kind of deal.