Thanks for adding the shots. And I'm sorry, but something doesn't compute. Johnny Bower played for the most defensive team of the era - the Toronto Maple Leafs, coached by Punch Imlach, featuring Tim Horton, Carl Brewer, Allan Stanley, and Bob Baun on D with Dave Keon and Red Kelly at C, and we're supposed to believe they allowed more shots than most teams?
When the Leafs had all those guys, they generally didn't allow more shots than most teams. When they were missing a few of them and most of the rest were getting old, then Toronto did allow more shots against than average.
1959: Bower 31.7, League 30.37 (Horton 29, Brewer 20, Stanley 32, Baun 22)
1960: Bower 33.0, League 31.50 (Horton 30, Brewer 21, Stanley 33, Baun 23, Kelly 32)
1961: Bower 32.0, League 32.20 (Horton 31, Brewer 22, Stanley 34, Baun 24, Kelly 33, Keon 20)
1962: Bower 31.1, League 31.72 (Horton 32, Brewer 23, Stanley 35, Baun 25, Kelly 34, Keon 21)
1963: Bower 29.7, League 31.97 (Horton 33, Brewer 24, Stanley 36, Baun 26, Kelly 35, Keon 22)
1964: Bower 31.5, League 32.89 (Horton 34, Brewer 25, Stanley 37, Baun 27, Kelly 36, Keon 23)
1965: Bower 31.4, League 30.37 (Horton 35, Brewer 26, Stanley 38, Baun 28, Kelly 37, Keon 24)
1966: Bower 33.6, League 31.39 (Horton 36, Stanley 39, Baun 29, Kelly 38, Keon 25)
1967: Bower 35.0, League 31.79 (Horton 37, Stanley 40, Baun 30, Kelly 39, Keon 26)
1968: Bower 34.3, League 30.39 (Horton 38, Stanley 41, Keon 27)
To reiterate, I think Bower was definitely helped by his teammates defensively, and maybe it's possible that his stats overstate his performance in other ways (as I posted before, home/road save percentage splits for that period are on my to-do list). But I don't think the shots against numbers can be dismissed simply by pointing to the Leafs' roster in those seasons.