I can appreciate this position but if you take it to its logical extreme, it would mean that the Royal York Hotel, TD Centre, City Hall and many other iconic Toronto buildings, which are now themselves a part of our heritage, never get built.
Likewise, 100 years from now, I feel like these Gehry masterpieces would be far more valued and revered pieces of Toronto heritage than these, then 200 year-old, warehouses would be. If built as proposed, they'll be uttered in the same breath as the buildings I mentioned above, whereas these warehouses never will. I make this trade every time, without question.