I'm curious as to why the cladding won't or can't be wood; there are other wood structures planned for Toronto, including one just a stone's throw from this proposal. Additionally, I don't think Google is going to do the usual Toronto style bait and switch when it comes to the renderings, since this is potentially one of the highest profile developments in the world..
A timber structure is very different from wood cladding.
A tall timber structure, while not yet permissible by the OBC, is reasonable and is permitted in other jurisdictions because you can size the structural members to maintain their structural integrity even during a fire (up to X number of hours) and because you can sprinkler them. I'm not speaking about light-wood framing here but large sized timber structural members.
Wood cladding is problematic because of its ability to burn and smoke, spread fire, an inability to cost-effectively prevent this, and because maintenance on wood cladding that is exposed to the elements is expensive and has to be very regular.
Timber arguably makes for a suitable large-building structure, but on large buildings wood does not make for a hearty, long-lasting or safe cladding. It's not permitted in code, and this will not (and should not) change.
The buildings you are thinking of, such as the George Brown College "Arbour" building will not be clad in wood. That is either a trick of the rendering (artistic license) or a material being misread as something it isn't (i.e. aluminum screenprinted to look like wood). The projects you are thinking of are buildings with timber structures, with glazing or wall assemblies with aluminum panel or other types of cladding covering the structure.
It's worth noting that many timber buildings are easy to mistake for being a typical steel or concrete structure because code requires the timber structural elements to be covered with drywall or other fire-resistant materials (in the case that the timber structural elements are not sized to burn for more than the required number of hours spec'd in building code). People imagine that timber structures have a certain 'look' to them and appear as wood buildings but it's possible that even on the interior, you wouldn't be able to detect the presence of timber. The exterior is similar - it could be covered entirely with brick, precast concrete, curtainwall, etc. The main takeaway here is that a building's structural material is usually a very separate matter from the way it is clad, both in terms of exterior cladding and interior finishes. At the end of the day, this is about life safety (fire), and the building's performance with regards to enclosure from weather, etc.
I hope this is clear / clarifies my post.