I'm going to disagree (and personally dislike the term "voodoo" when talking about goalies). Many factors come into play when developing a young goalie. In the case of Wallstedt, he's been a standout since a very young age, is very technically sound, and is currently adapting to his 3rd year in North America.
Team system of play and team defensive structure are also key factors in goalie development. How many shots does he see a game? What type of shots (high/low danger)?
How is he being developed? His lateral movements, glove hand, stick handling, timing, etc etc. It's not voodoo, it's a full system of development. Some goalie coaches are much better than others, many goalies (especially those with a higher pedigree) are given much more opportunity. Team development system at each level is important.
In this specific case, I see Wallstedt with the upside of a no.1 goalie, while being on a team with a good system to develop his skills. Knies I see as a very good 2W with the ability to fill in at 1W if need be.
If developed properly by each team, I'm easily taking the 1G over the 2W.. but again, that's if everything breaks right for each player based off of the systems they are currently in.
I could see him being a complementary player, like a Boldy-lite.
