From the early 1990's onwards (ie after Lemieux firmly established himself as one of the Big Four - which I'd argue was no later than spring 1992), Maurice Richard seemed to be almost universally considered the #5 player all-time. It's not that you didn't have people argue for Hull or Morenz (as examples), but he seemed to be the most common pick for the 5th spot by a wide margin. It's only been in the past 15 years that his reputation seems to have dropped.
I agree with TDMM - part of his reputation was as a French-Canadian icon. Growing up in Quebec (though as an anglophone), it's hard to exaggerate his cultural significance. Of course, cultural significance and playing ability are separate concepts - and I often wondered (as an outsider, looking in on French-Canadian culture) if his fanatical fans were conflating two different things. Still, he seemed to have widespread support from nearly everyone (francophone or not).
It seems like over the past 15 years or so, there's been an over-reaction in the other direction. I've seen people say (on the main boards - for whatever that's worth) that it's laughable for him to be considered a top ten player all-time. The main knock on him is he never won an Art Ross. That ignores that, had he not peaked at the same time as peak Gordie Howe, he'd have at least two scoring titles (1951 and 1954), and probably three (1953 - depending on what Lindsay did without Howe). Add to that a very long, consistent prime (14 consecutive years as a first- or second-team all-star), a ton of consideration for the Hart trophy ("only" one win, but six times a finalist), and a (deserved) reputation as arguably the 2nd greatest playoff performer in NHL history - and there's a pretty clear case for him being in the top ten.
As a player, he has his weaknesses. His playmaking is comparatively poor (I've made the same criticism of Hull and Ovechkin). His most famous accomplishment (50 goals in 50 games) was done when the league's talent was depleted. There are different accounts of his defensive play, but it seems to range from average to poor.
All that being said - I had him ranked 12th when I submitted my list for the top 220 project. I suspect that's pretty low on HOH. But having him in the top ten is perfectly defensible. And if we're strictly talking about importance to the history of the sport and cultural significance (rather than playing ability), I think only Gretzky would be unquestionably ahead of him.