The debate is over and at leats now developers and Waterfront Toronto can develop future plans with certainty and that's a good thing.
I would have preferred a teardown but Toronto can still create a wonderful Waterfront that is far better with the Gardiner than without. Seeing Lakeshore will be redone, the entire area under the Gardiner is a clean slate. They can make it a pedestrian wonderland as long as they don't allow any bikes which guarantees little pedestrian life.
Cover the enire underside with beautiful wood panelling, old style lamp fixtures, cafes, restaurants, food stalls, clothing stores.......make the Gardiner a "go to" place. A combo Yonge/Queen/Kensington Market. The area where people in the Waterfront/Portlands go to do their shopping, entertainment, get a drink, grab a bite to eat, watch street performers, buy their fresh produce or meet friends for a coffee. The entire stretch from Yonge to the DVP could prove to the world tha elevated urban expressways can be a city's best friend.
An area where after walking down Yonge and taking in all the weird sights and sounds people don't stop at Union but keep going and "do the Gardiner". The Gardiner could become Toronto's urban oasis that unlike any other offers a 4 season. Toronto is a winter city and the Gardiner could be the place everyone wants to see and be seen even when it's raining or snowing.
It's true that this was a decision for 100 years and it could turn out to be one of the best the city every made. If Toronto gets this right, in 20 years to 100 years from now people will be looking back and commending Tory and the current councillors for having the wisdom to keep the elvated highway and people will say "thank god they didn't tear down the Gardiner".