I think there were some good arguments made for the 1920s goalies vs. the 1940s generation, which caused me to drop Broda a few spots and move Vezina and Benedict up some. At the moment I have Brimsek, Gardiner, Parent and Vezina (in some order) as my top four this round, with Benedict and Esposito narrowly behind them and still in contention.
Yeah, that's what I'm thinking. I also value how much Esposito dominated his own backups statistically. Parent can't exactly say that (hell, Stephenson gets them to the Cup in '76 just the same). I'm just trying to gauge the feeling of the group and if I'm missing something important here. It seems Parent is above this obvious divide above Esposito...and granted Parent's two years were amazing and Tony O had his playoff struggles to whatever degree...but I keeping looking for "what else" with Parent and every time I check, I think I sour on him a little more.
I don't really think there necessarily should be a very obvious divide between Parent and Esposito, who also has a great regular season record. I think you are raising some legitimate points with comparison to backups, but it is important to point out that the talent level of backup goalies in the NHL during the WHA era was generally pretty low, and therefore quality of backup goalie needs to be taken into account in any performance vs. backup comparison.
Wayne Stephenson was certainly not a career backup. He had three seasons as a starting goalie outside of Philadelphia, all of them with a save percentage right around league average. Stephenson took a while to get to the NHL, but that was mainly because he played for a long time on the Canadian national team. By his second pro season he was the starting goalie on a playoff team. He also played in the NHL until the age of 36, at a time when it was typical for most goalies to retire at a younger age.
In addition to Stephenson, Parent also played with Gerry Cheevers and Eddie Johnston in Boston, then Doug Favell in Philadelphia and Jacques Plante in Toronto. That's a much, much higher level of goalie teammate ability than his '70s rivals Esposito or Dryden, who both saw their most frequent backups pretty much crash and burn as soon as they moved on to play for weaker teams (Mike Veisor: .901 in Chicago, .862 in Hartford/Winnipeg, and Michel Larocque: .894 in Montreal, .855 with TOR/PHI/STL).
If Philadelphia never traded for Stephenson and went with weaker backup goalies, Parent would have dominated his backups by a lot more, as his numbers were much better than those of Bobby Taylor, Gary Inness, Rick St. Croix and the other truly backup-calibre Flyer goalies of the '70s:
Philadelphia Goaltending, 1973-74 to 1978-79:
Parent: 177-60-57, 2.25, .914
Stephenson: 93-35-22, 2.77, .897
All others: 15-13-6, 3.33, .882
I think once you properly account for quality of teammates, Esposito's dominance over his teammates is very good but does not stand out by as much as it seems to at first glance relative to Parent. Esposito did not have much of an edge over two pretty decent goalies in Gerry Desjardins and Denis DeJordy during his first two seasons as a starter (.926 vs. .921). Esposito also didn't have much of an advantage over Murray Bannerman in his late career, although those weren't exactly seasons that add much to his legacy anyway. The argument that Esposito owned his backups is entirely based on 1971-72 to 1977-78, when Tony O had a .913 save percentage while his backups combined for just .887.
Esposito's '71-72 and '72-73 seasons were in fact extremely impressive in this regard since his backup goalie was Gary Smith, a long-time NHLer who was a starter both before and after his stint in Chicago yet managed only .897 in 51 games in Chicago compared to Esposito's .924.
Over the next five seasons, however, Esposito's backups were the aforementioned Veisor, an over-the-hill Gilles Villemure (.854 in 22 GP), and career minor-leaguer Michel Dumas (8 GP). Veisor was so bad in 1974-75 that the team demoted him and replaced him with the 35 year old Villemure, but by the next season it was clear that Villemure was washed up and Chicago ended up having to turn back to Veisor again. Esposito had a .910 compared to his teammates' .879 from 1973-74 to 1977-78, which is a gap that is almost exactly equivalent to Parent's lead over non-Stephenson Flyer teammates up above.
One thing to note in Esposito's favour though is that since he played so many games per season it is very possible his backup goalies faced slightly weaker opposition on average, which may have slightly inflated their numbers relative to other backup goalies.