At one point you could say the q was the most successful, pumping out all time greats like Lemieux, Lafleur, Lafontaine, hawerchuk, bourque, bossy, roy, brodeur, robitaille, and many other great french players. But recently they havent seen too many future hhof type players come through except crosby. Right now the best league is the OHL having the past 4 1st overall draft picks coming from there (hall, tavares, stamkos, kane). IMO the W is ranked 3rd on the all time list having the least amount of greats and no players in the discussion for best all time. The q has lemieux lafleur and bossy all whom were at one point the best in the NHL. Lemieux in the discussion for best all time, lafleur possibly best of his era, and bossy often regarded as best goal scorer. They also have the 2 top goaltenders of all time in wins. Brodeur and Roy. OHL has gretzky, often considered best all time and orr considered best D all time. The whl doesnt seem to have a player like this, sakic being the closest thing probably. Not saying he wasnt an amazing player but he isnt going to be considered as the best of all time by any means. Also, the whl hasnt seen a 1st overall pick since 1996 and it was chris phillips.
Past few years I would rank:
1. OHL
2. WHL
3. QMJHL
All time:
1. OHL by a hair
2. QMJHL
3. WHL