AoD, those heritage gems (if they can even truly be considered gems) you speak of not only form a minority of the building stock on the stretch of Yonge in question, but they also don't match the context of the street, given its new surroundings, and its important role in the city. In addition, there are many Victorian buildings in other parts of Toronto, and I'm not talking about houses either. Anyways, I'm not advocating the demolition of every single building on Yonge, I'm just saying that it's incorrect to turn "heritage" into a blanket term that covers everything built prior to 19XX, thus covering nearly the entire street. Buildings should be preserved for architectural merits, and a few other reasons, but the construction date should certainly not play such a large role. Expecting streets to remain the same and keep their "feel" indefinitely, regardless of any benefits that a complete makeover might bring to the city is an example of complacency.
As for the view vistas and shadowing issues, I don't bring those up as a form of trolling, but rather to highlight the (in my opinion) poor prioritization of principles at city hall. There are many ways in which the city can at least guide developers to create more engaging urban spaces. However, (and I challenge you to prove otherwise) the majority of their concerns seem to focus on height, shadows, etc., while completely disregarding design, and street engagement (aside from the occasional traffic quibble).