It definitely does open a can of worms, but we're alreayd doing essentially just that in comparing players across eras.
You're not really comparing them across eras, as I understood it, though - you're measuring them against the quality of play that existed in their era, and basing the rankings on that evaluation. That's a measurement that can be made relatively easily; we have statistics and other documentary evidence that shows how a given player compared to his contemporaries. Even when the evidence is sketchy, as it often is with pre-1960's European players, there's almost always enough to at least make an educated guess by doing things like examining how well they played against North Americans for whom a more definitive assessment can be made. In short, the material is available to make an evaluation that's reasonably objective.
But how do you evaluate "state of development" on a nation-by-nation (or even region-by-region) basis? There are no meaningful ways to compare the hockey played by Vsevolod Bobrov, a professional athlete in all but name, on a state-organized team surrounded by world-class athletes, with that played by Dan Bain in his off-work hours for a team he joined when it ran a newspaper ad offering tryouts. Fifty years and vast changes in the game separate them. The only slightly similarity is that hockey had been introduced to their respective countries a similar amount of time earlier. Yet it's suggested that they represent the same level of development? That's a purely subjective statement that can't be backed up by any concrete evidence.
To consider where this line of thinking takes you, consider Erich Kühnhackl. Czech-born and -trained, played his entire adult career in (and for) Germany. So, do you evaluate him according to the Czechoslovakian players of his generation, or the Germans? Or Helmut Balderis. Latvian, but played most of his career while Latvia was part of the USSR. Is he evalutated to a different standard than, say, a Russian of the same era like Sergei Makarov? Or Mike Buckna: star of the early Czechoslovakian game, pretty good senior league player and fringe NHL prospect when he returned to Canada, where he had learned to play in the first place.
And those countries - the game has been around for roughly the same amount of time in Germany and then-Czechoslovakia. But by Kühnhackl's time, the Czechoslovaks were clearly playing at a higher level. So if Kühnhackl is considered German, does he get evaluated to a softer standard than Milan Novy, or the same one? And Latvia was playing internationally more than two decades earlier than the USSR - does that mean the game was more advanced there, despite Russia clearly being the center of the Soviet hockey universe?
Those are the kind of calls you'll have to make to set up some standards for the list. And every time you make them, you'll be doing so based on much vaguer evidence than you used for evaluating players on the first go-round. Is that going to produce a list more meaningful than the first one?
