Toronto wasn't meant to become the largest city in Canada, let alone top the list in North America, so a lot of the lagging in design and infrastructure people complain about is really a symptom of that, along with the resistance to the idea that Toronto even could be a world sized city (fighting large developments, fighting transit etc).
Anyways, something a little more on topic to this building that had me thinking.
The decision for cheap materials on the back here is really a failure of city policy, plain and simple. Cities really shouldn't be designed to have a presentable pretty front face where the rear ends up ugly and only serves the purpose of utility, that's bad city building. Many alleyways in other cities serve more than just the purpose of being a garbage dump. A college friend from the UK even specifically asked me why North American cities focus all the design to the front building face, it caught me off guard, so this issue isn't going unnoticed.
Ignoring the Mercer Street facing side, and focusing on the alleyway: This block will be the most dense feeling in the city by far, quite literally Hong Kong levels of density, yet the 'city' part is a failure due to the lacking ground level experience. This alleyway is a prime example of city policies that build utility alleyways that not only encourage cheap finishes as seen here, but make for something useless to anyone other than a delivery truck driver. It's hard to blame a developer for not caring when the city designates the space to be utility only and to lack any vibrancy. Nobu and the surrounding area could be quite vibrant if the space within and around the alley and along mercer was originally built for micro retail and markets.
I do agree that the developer really shouldn't throw up those materials on a proclaimed luxury build, but if the back of the design also had to interface with the laneway I could see that the spandrel you are seeing would be toned back significantly. Alas the city wouldn't want that, or even if they let it, it's actively discouraged with no amount of nice hardscaping. Which is too bad, because narrow vibrant side streets away from *most* cars would be a dream for the city.
I'm not arguing that every back alley needs that level of treatment, understandably some do house many utilities, but this is the Entertainment District after all. There is quite literally thousands of people that will live within this block and yet there is nothing to do within the block. But every alleyway deserve some type of dignity, through hardscaping.
(Google Streetview)
Melbourne has many great alleys in their core,
but many are created artificially which is what should have been done here (i.e planning for market streets over utility streets),
this example is more organic and just happens to have businesses within it. Oh look it still functions as an alleyway even with added vibrancy, wow who knew.
(Google Streetview)
And a more extreme example: The same density and width as the Nobu alley, a little more grit but a lot more people. Alleyways in Hong Kong are more narrow than most cars, so by comparison our alleyways are like their streets anyways.
(Google Streetview)