I think if you carved out similar central parts of both cities the story wouldn't change much, because a lot of the more interesting parts of Toronto are downtown too. But from my perspective, the oldest parts of Quebec have maintained a fine-grained neighbourhood character, and this is one of the strengths of that city. A lot of the development that might have taken out the nicest blocks of Quebec instead ended up in places like Ste-Foy.
I'm well-acquainted with the great wealth of distinct neighbourhoods in Toronto and Montreal, and I know exactly what a place like Winnipeg has to offer, but I don't know much about this aspect of other places. Thing is, so far it seems like people are mentioning community organizations and historical architecture instead of what I'd thought the intention of this thread was.
To me, historical architecture can be a major part of what makes a neighbourhood great. I don't think people would like Paris or Amsterdam as much if they were all 1960's concrete (there are densely built-up European neighbourhoods with post-WWII architecture and they tend not to be as popular). I get a lot of joy out of exploring cities and seeing hints of what things used to be like, and evidence of past events. There's often a level of craftsmanship in older buildings you just don't seen in newer construction (I mean 1600's vs 1700's vs 1800's). Like I said, I also find endemic culture to be more interesting.
I don't mind the 1910's and 20's commercial blocks but they are just not the same. I'm sure somebody from Rome might say that the 1700's buildings in Canada aren't impressive either.
My impression of your opinion on this matter is that you more or less imagine scaling up what each city has to offer by looking at its population. I think this is somewhat true in smaller areas like Ontario or Western Canada but falls apart in Eastern Canada. Quebec City is not like Winnipeg or a mini Toronto. Halifax and St. John's for that matter are not mini Torontos or Winnipegs.
The city with the greatest density of historic neighbourhoods (pre-20th century) in Canada is Saint John NB. There are literally places where you get Victorian houses and shops next to rocks and trees around the undeveloped fringe of town. European settlement there goes back 400 years and you can bump into Benedict Arnold's house, etc. It's not at all what you'd expect if you imagined it looked like a arbitrary Ontario or Alberta city scaled to 120,000 people.