In rebuttal:
1) His first two playoff years, howevere, were aboslutely FANTASTIC. A retro smythe, 11 points in 8 cup challenge games, and 7 points in 4 NHL playoff games. Simply dominating.
His numbers do drop off after that point, but at the same time, the playoffs were rather short and saw the two best teams going against eachother often times- didn't leave much room for proving yourself of wracking up points on bottom feeders like many more modern players get to do.
Besides this, he gets hindered in a sense when you look at a spectrum that large, as it's harder to keep pace when you're playing 10+ more games at an older age than some of the other guys who come ahead of them looking at 193-1937 PPG.
He was not the most dominating player ever, but he has good longevity as well. And one must remember that Morenz couldn't just dominate offensibely- he was called the best backecheker of his day, would go through people if not around them, and was quite gritty as well.
Having 3 hart trophies, tied for fourth most, certainly helps his case as well- especially as the hart trophy wasn't around for the first part his career. (to my knowledge)