They did, though. They made them really good. His shot totals in a season aren't statistically significant to draw any meaningful conclusions from - positive or negative. Even in the NHL, with more games and shots, normal statistical randomness with goalies takes several seasons to parse.
This goes into the issue with our current goalie stats and why it's tricky to draw meaningful conclusions from what we would traditionally consider meaningful numbers:
I know it's frustrating to have someone say, "None of this matters," and then shrug. I appreciate your post, though. It gets me thinking and it's nice to see his progress charted. Unfortunately that's about all we can do right now with Cossa. Goalies are indeed voodoo. I think current goalie scouting is quite a bit better than the past and the traits of winning goalies in the NHL are becoming more refined, but it's still a hugely mental position that is difficult to project long-term.
Here's my current stance:
He has every god given tool to be an exceptional NHL goalie. It's why Yzerman jumped to grab him. It's all there. He's got all those physical gifts that
should see him succeed. What happens next, well, that's up to him.