At risk of stating the obvious, part of this discussion will never be resolved because it's emblematic of a perpetual tension in architecture, which is the question of who are the most "important" arbiters of the "quality" of a building. The irony (and, depending on how one looks at it, shortcoming) of much contemporary architectural critique is that the buildings that industry professionals and critics tend to like (painting both with very broad strokes, of course) and those that "the masses" tend to like are often quite separate.
In my experience, most laypeople (I don't use that term pejoratively here) sort of hate some of the buildings that are some of my favourites, like Rogers' Lloyd's building or the Piano/Rogers co-pro Pompidou; on multiple occasions, I have walked by each of those buildings and expressed my love for them to the non-arch geeks I was with, only to have them tell me that I have terrible taste and that those buildings "don't even look finished."
And, on the flipside, similarly non-geek-type friends have repeatedly expressed to me their love for, say, some of the swoopy Zaha buildings that I find to be unrefined and overwrought. (This is obviously a reductionist and imperfect illustration, but there are many other examples of similar divergences in popular vs. niche opinion.)
I totally get that when we finally get a Piano in the city, folks would like it to be more than a background building -- I absolutely share that sentiment. But I also think that there is value in seeing buildings that don't have a grand architectural flair or an aggressively obvious parti added to the landscape in Toronto, both because so much of our architecture deeply lacks for excellent detailing and also because it provides an opportunity for the design-obsessed to educate the non-geeks -- or at least to inform them with respect to what it is we like about certain buildings that don't necessarily catch non-geek eyes.
All is to say, I think all of the following can be simultaneously true:
> It's great to have a Piano-designed building in Toronto and we'd love to have more of them;
> It would be great if the next Piano-designed building in Toronto were more of a showcase;
> It's totally reasonable to celebrate the expected superior quality in detailing we're likely to get here;
> A lot of folks nonetheless won't think this is anything more than a glass box;
> This building should provide a good opportunity for fellow geeks (I use that term endearingly throughout) to bring along some of their friends, colleagues, or acquaintances and help them see and critique their built environment through a new lens.