Yes, some of the proposed and under-construction projects will definitely beautify the city, and not just downtown (East Harbour, the Mr. Christie site, etc). Sadly, not this one, although you could argue that it's better than the current parking lot ...It is getting prettier, inch by inch, day by day. There's no reason why some day it can't be one of the most beautiful in the world. We just need to continually demand better and not settle. Berzcy Park, The Well, Bloor Street Improvement Project, etc. It can be done and one doesn't need a massive inventory of pre-WW2 buildings to accomplish it.
Agreed with 1970-71: Ontario Place did not open until May, 1971. While it's fuzzy in the background of this photograph, and we cannot be certain of its stage of construction, it's definitely there… so yes, one or the other of those two years, and I'm tending towards 1971.Assuming all the photos were taken at the same time, we can narrow down the time range substantially.
We can see that the Simpson Tower looks complete, that was 1968.
We can see that the St Lawrence Centre looks complete, that was 1970.
We can the Sheraton Centre under construction, it would open in 1972.
So that puts the photo series somewhere in the 1970-71 range.