A clever recurring reference among some Oiler and Flames blogs is to the "cowbell" of a particular fanbase or coach. You can read the history of this expression at the blog that originated it, Five Hole Fanatics, but in essence it refers to a specific skill or attribute that gets a disproportionate weighting in player evaluation (the name came from the famous SNL skit where Christopher Walken was obsessively focused on the sound of the cowbell).
The absence of Martin Brodeur is making it pretty obvious that New Jersey fans have a couple of cowbells in terms of evaluating goalie play. They are rebound control and puckhandling. Take a look at this HFBoards thread where Devils fan after Devils fan piles on Scott Clemmensen for his poor rebound control and his lack of Brodeur-esque puckhandling skills.
Apparently whether or not Clemmensen actually stops the puck is pretty unimportant, it is the style with which he does it and the way he handles it that is critical. I don't mean to downplay rebound control too much, since obviously poor rebounds create goals against, but the majority of rebounds are cleared away by the defence, and the majority of rebounds the other team does actually get to are stopped again by the goalie.
If Devils fans are correct in their assessment, then that strongly suggests Clemmensen has been better at making the first save than Brodeur. I don't have the exact comparison, but let's say for example that Brodeur gives up one rebound shot per game while Clemmensen gives up three, and that goals are scored on 25% of rebounds. That allows us to estimate the first shot save percentage for each of them:
Clemmensen: 25.6 1st SA/60, 3 reb/60, 2.36 GAA, .937 est. 1st shot sv%
Brodeur: 24.7 1st SA/60, 1 reb/60, 2.16 GAA, .923 est. 1st shot sv%
I think the other teams this season have been throwing a lot more perimeter shots on net against Clemmensen than they have against Brodeur, which might explain both the shot differential and why we could expect Clemmensen to have a strong first-shot save percentage.
This leads us to a hypothesis of goaltending play: Given how few rebound shots are actually taken in a typical hockey game (about 3 per game for both teams combined, according to one study), the effect of a goalie who is great at controlling rebounds might not just be allowing fewer second chance shots, but also facing fewer total shots by deterring the opposition from shooting in the first place. One of the main reasons to shoot from a bad angle or a long distance is to try to create a rebound, and if the shooters don't think they will get one then they are more likely to pass instead. The game score evidence that I have been working with lately shows that shots are to some degree discretionary (teams shoot substantially more often when trailing, for example), so I am starting to think that perhaps the main cause of the observed shot differentials between goalies may not be the direct effect of them giving up a lot of extra rebound shots or not being able to clear the zone, but because for whatever reason the other team thinks it is good strategy to put more or fewer pucks on net. Even if this is true is still could be argued that excellence in those types of goalie skills do effectively "prevent" or "create" shots against, but because the effect is indirect it would not be as easy to isolate it as it would be to, for example, count rebound shots.
Speaking of counting rebound shots, I am interested in seeing The Forechecker's rebound numbers for this season to see if perception matches reality in New Jersey. If we could isolate Brodeur's rebounds per game vs. Clemmensen's, that should be able to give us a sense of the direct impact of a goalie in terms of rebound control given the discrepancy between the two of them in that particular skill. Whether great rebound control can impact goal prevention indirectly through shot prevention is a topic that requires more study.