Perhaps one of the major stumbling blocks I have encountered when trying to spread my particular message about goaltending play is that many people evaluate goalies based on talent, rather than performance. This may seem like a small semantic difference, but it is a crucial one.
There are a lot of players in the league with an abundance of talent, but lacking the performance to match. Chad Kilger of the Toronto Maple Leafs is such an example. Kilger is one of the fastest skaters on his team, and last year was clocked with the hardest shot in the league. He has size and decent hands. By all rights, Kilger should be a star player. But he is just a third liner, and the reason is that his talent does not translate into production. He's played for 6 different franchises, and has just 201 points in 661 career games heading into this season. You can watch him play a few nights and think that he is one of the best players on his team. Over the course of an 82 game season, however, he simply proves that he is not.
Performance is the difference between the player Randy Moss was in Minnesota and the Randy Moss in Oakland. It's the difference between Marc-Andre Fleury and J.S. Giguere. It is the reason that you can't trust your eyes and the highlight reels to evaluate goalies. If a goalie makes a great save and then lets in a really soft goal, he's no better than a goalie who lets in the tough one and stops the gimme, but often it is the great save that sticks in our minds and influences our perceptions. When it really comes down to it, it's not how you stop them, it's how many you stop, because hockey games are decided by goal differential, not style points. You have to look at the numerical record, because that is the only objective and comprehensive record of a goaltender's performance over the course of a season.
Martin Brodeur is a talented goalie. He is a great puckhandler, he controls his rebounds well by most measures, he is a good skater, he is athletic, he has great reflexes. Watch him, and you'll probably be impressed by something. But look at the stat sheet and divide his number of saves by the number of shots he faced, and you'll think you made a mistake, because the number is lower than perception would indicate. This is the talent/performance gap in action.
I believe the gap is sometimes very high for goalies, because of the overarching importance of positioning and technique. Cristobal Huet is one of the top goalies in the NHL, and it is not because of his talent. He has somewhat slow lateral movement, he doesn't have outstanding reflexes, he's not one of the best puckhandlers. Yet look at his save record, and it is great. This is because his positioning is usually perfect and his technique is very good. In today's high-speed NHL game, those things are more important than raw talent. Another example is Giguere, who has been frustrating opposing fans for years because he doesn't look like anything special. He is always optimally positioned and moves around in a compact block, making it very tough for shooters to pick the corners on him. Dominik Hasek was considered lucky for years because he had an unorthodox technique, but his fabulous save statistics showed that he was massively outperforming his peers who were doing things "correctly".
Talent is easier to evaluate than performance. Even professional players and scouts often fall for it, but that doesn't make it any less of a trap. Most seasoned hockey fans can tell which goalie is more fluid in his movements, who covers more net, who handles the puck better, who catches/absorbs more pucks, etc. But the difference in save percentage between top goalies is often something like .005 or less (or even .001, as last year between Luongo and Brodeur). This translates to one extra save for the better netminder every 8-10 games, which is an impossibly small margin to reliably detect based on observation alone, and that's not even taking into account team factors like shot quality against.
I place a heavy emphasis on numbers because they eliminate selective memory bias and excessive focus on talent, and look only at the most important issue: How effectively did the goaltender keep the puck out of his net, subject to the team conditions he played under? That's the bottom-line consideration that everything should be based on, because hockey goaltending is a results-oriented profession: It's the performance, not the talent, that truly counts.