I don't understand why people want Toronto to look like Manhattan? No city will look as much like Manhattan as Manhattan so it seems sort of silly to have this as an objective. In my experience nobody comes to Toronto to marvel at the highrises. They come here and end up loving the dense low-rise urban communities that flow from one to another in and around the downtown core. This is what is so vastly different from 'most' North American cities. The downtown core and skyscrapers are all great too, but they don't define Toronto anymore than 'downtown' LA defines it.
I don't think people want Toronto to look like Manhattan, but there's definitely a sizable proportion of the population that lives here, or moved here because they love big cities and all the delights that a big city offers. Toronto is as big as you can get without leaving Canada, so it's only natural that some people just can't wait for the city to add another 5 million people, 300 km of subway, build another 6 museums, and another 50 towers over 250 metres.
That doesn't mean they want to be Manhattan, it means that they love big cities. Toronto is Toronto, and will always be Toronto. There were people back in 1970 who wanted Toronto to stay the way it was arguing that growth meant that Toronto would become less Torontonian and more something else. Well, I'd argue that Toronto is still Toronto, and 100 times better than it was back in 1970.
I also think you're assuming too much when you say that people don't come to Toronto to admire the skyscrapers. It's Torontonians who appreciate the neighbourhoods, but I can guarantee you that it was the tall buildings and the CN Tower that I came to see. It's also one of the reasons I chose to move here. Chicago and New York may be more famous for their skyscrapers, but to a Brit it didn't matter to me. A 200 metre office tower was something I'd never seen before, and Toronto had them. You might be surprised or find it strange, but I guarantee you that people still come here to gaze at the tall buildings. Toronto is a skyscraper city in the eyes of most of the world.
Was Hong Kong trying to be Manhattan by building vertically? No. It's just the what many cities do when they reach a certain stage of their development. Toronto may be a city of neigbourhoods, but it's also always been one of the world's early skyscraper cities. Royal York? Commerce Court North? Canadian Pacific Building?