2) No, I don't agree. If you decide to weight the WW2 years as 50% then what about the 70s when the WHA took a bunch of NHLers? What about every season up to 1989 because there were no Russians in the NHL? What about this season - the Chinese haven't taken up the sport yet - there are a billion potential players.
It isn't Herb Cain's fault that some players were at war. It isn't Bobby Orr's fault that some players jumped to the WHA, it isn't Wayne Gretzky's fault that there was an iron curtain, just as it isn't Sidney Crosby's fault that 1 billion Chinese do not play the game. If the NHL plays then, the stats are earned against the best the NHL could offer.
I am not one to say that x year was easier than xx year. An NHL season is an NHL season in my books. Every season is going to have its issues. Should we revoke Wayne Gretzky's 1994 scoring title because Lemieux was out of the Penguins lineup? Perhaps Phil Esposito doesn't really deserve the 1973 goal scoring crown because Bobby Hull was in the WHA that year? Is the Oilers 1990 cup illegitimate because Gretzky was injured while they beat the Kings?
I don't buy into the idea of making certain seasons worth more than others.
There is just no comparison between what happened in WW2 and any other circumstance regarding talent dilution in the history of the game. A few players missing here or there doesn't compare to an absolute gutting of the majority of the league to create a situation where a few leftover legitimate players were able to dominate minor-leaguers. The WW2 situation deserves special consideration because it was
exponentially more traumatic to the league talent base than anything else which has ever happened.
80 players scored more than 40 points in the NHL in 1971-72. 5 of those players moved to the WHA, and 2 (Gerry Pinder and Bobby Sheehan) were nobodies from the California Golden Seals. That's a 6% loss of talent. The only guys of note to leave for the WHA were Hull, Tremblay, McKenzie, Ted Green, and Gerry Cheevers. A couple more guys (Stapleton, Tardif) left a year later. The WHA was built on fading 35 y/o players cashing in on a big last payday, and on journeymen who were 4th liners and 6-7th defenders on NHL rosters.
Only a couple 'great' players were playing in the WHA at any given time who could have significantly affected the NHL scoring race or awards voting - from 72-79 these were still fairly 'true' representations of the best players in the game. A 3rd-place finish in Hart voting in 74-75 might be equal to a 4th-place finish outside of that period ... not a huge difference.
Compare that 6% loss to the 60-70% of players from 41-42 who would miss most/all of the war period. 16 of the top 21 scorers in the league in 41-42 would miss at least two full seasons of play. That's pretty much 10X the effect of the WHA or anything else in league history.
No-one considers guys like Cain, Hollett, and Lorne Carr anything close to all-time greats, and it shouldn't be reflected as such on your list. These were average players who were fortunate enough not to have to go to war, and had the double bonus of being able to pad their career stats against AHLers in the meantime.
Any system which gives Cain the same credit for his 43-44 season as guys like Howe, Orr, and Gretzky received for their dominating seasons is flawed. These guys shouldn't receive no credit, but it has to be mitigated to a certain extent if you want your rankings to have credibility.