1) Your point on source of population growth is not true.
Toronto knows how many people come there as a function of overall migration and is a very active participant in migration policy.
Moving 100K people / year into Toronto is part of the plan.
On a national level, we plan for this, knowing very well how many are going to Toronto.
2) Toronto does not grow 'because it's a great city'. It's only 'great' relative to the options of most of it's poor migrants from Philippines, China, India etc.. Having a 'decent government with basic laws' is not 'great', it's just 'normal'.
(Edit: I grew up in Toronto hence my strong opinion, and wasn't able to put it in perspective until I lived abroad in many places)
Ironically, for all of it's 'multiculturalism', Toronto is actually a very bland, uninspiring, nondescript place where nothing really happens. It's mostly American big box retail, foreign cars, nondescript architecture. Toronto has tons of Starbucks', Tim Horton's.
It actually 'has everything' (i.e. the Opera House, decent public transport, major sports teams) - all the checkmarks, but nothing stands out on a world class scale. Toronto is a grand exercise is 'basic civic function' but almost nothing more than that.
To given an example - Toronto doesn't even have a single Michelin starred restaurant. Not one. Ever. Chicago has about 20. Seoul has about 20. Not that Chicago and Seoul are 'better overall' - but they have enough identity, character, soul, character, productivity (i.e. money) to do notable things.
Can you name a single product or service designed in Toronto that anyone, anywhere else is the world can name? Or uses? Can you name a really important international company HQ'd in Toronto?
Admittedly, being able to incorporate a lot of people very fairly from around the world and get them education, jobs, integrate them fairly well - is in fact something 'notable' for which Canada/Toronto doesn't get enough credit. We should be proud of that. But beyond secular civic issues - Toronto is a 'non place'. This is why people that have established roots in more aspirational places are not flocking to Toronto.
People 'flee' to Toronto to escape crappy conditions.
People from Kyoto, Stockholm and Zurich are not thinking 'oh, we really need to move to Toronto, they have so many Starbucks'. They're not coming.
3) "Where we do agree is in what should be done: zone for tall buildings and dense land use"
I don't really agree at all. I say cut the number of people coming to the city substantially (i.e. normalize the rate of immigration) which would entail obviously a national strategy, and also put some special conditions on foreign speculation.
After the last 20 years of re-construction, Toronto already has enough density.
I don't see any point at all in growing into a massive, vertical city with tons of traffic and density is positive in any way, for anyone frankly.
Then we can talk to Google about some things for which they have great expertise: information management and connectivity (i.e. not building neighbourhoods), and hopefully do it in a way that respects people's privacy.