I have also been thinking that the findings of modern load management should update our analysis.
But I'm not sure what to make of the actual data. Have you looked at the days by rest report on nhl.com? Most goaltenders' save percentages with 0 days rest are similar to their overall numbers.
For example Martin Brodeur has played in 180 games with 0 days of rest. Of all goalies in the last 50 years*, that's over 50% more than #2. His save percentage in those games is 0.912, identical to his career save percentage of 0.912.
Others with similar numbers. Maybe Roy and Hasek were worse with 0 days of rest, but the statistical difference is only about one standard deviation.
Ed Belfour - 0.906 overall, 0.911 on 0 days rest (106 GP)
Dominik Hasek - 0.922 overall, 0.918 on 0 days rest (103 GP)
Curtis Joseph - 0.906 overall, 0.904 on 0 days rest (93 GP)
Patrick Roy - 0.910 overall, 0.905 on 0 days rest (91 GP)
Henrik Lundqvist - 0.918 overall, 0.926 on 0 days rest (90 GP)
Roberto Luongo - 0.919 overall, 0.919 on 0 days rest (84 G)
It's possible these numbers are skewed by selection effects, where goaltenders have only been played in the easier back to backs. Although Brodeur played 70% of 0 days of rest games on the road, so I'm not sure that's the case for him, at least.
And the 0 days of rest data doesn't speak to the fatigue or wear and tear that a workhorse goalie might accumulate by the end of a season.
With regards to Brodeur, I wondered if his style played a role, and if the modern pro-fly style needs more recovery than some styles of the past. I see
@Michael Farkas is thinking along the same lines.
*I wouldn't draw any conclusions from 0 days of rest data from the Original Six. Each team had it's own specific travel schedule where some teams played their back to backs at home and others played their back to backs on the road. Days of rest data from that era can't be compared across teams.