I guess it's because Toronto winters are never monochrome-bleak!

Yup - red brick would be far more appealing. Still, it's miles better than what it replaces and no one can seriously argue that it's out of scale for the neighbourhood.
4200 clear is pretty low for modern retail. The city normally dictates a minimum of 4500.

The city requires a floor-to-floor height of 4.5m. This one is 4.6m. The clear ceiling height is a different thing altogether, for which the city doesn't have any specific requirements - in this case it's 4200 because of the thickness of the structure. It would be around the same height with a 4.5m floor with a 200mm floor and drops at columns or transfers, though you don't typically see small scale buildings made of poured-in-place concrete because it's not economical at this scale - something the city doesn't really consider in coming up with these guidelines. 4.5m F-F applies whether it's poured in place, steel trusses, wood frame, etc. And the F-F height doesn't even guarantee that'll be the finished ceiling height, because some designers (the ones doing the retail design later on) will leave it bare, others will put in a dropped ceiling to hide all the ductwork.

I have the feeling, as I have on more than a few occasions, that the city is prioritizing height here to the detriment of overall design. Is it really better for the city to demand that a builder reduce overall height by a couple of feet in exchange for low ground floor ceilings? Is that going to improve the vitality of the street in any measurable way? Is shaving 1' 11" off the height of a building really going to change its impact on the heritage of the street? Who benefits from that kind of slavish adherence to rules? I have so many questions! I mean, it's a four-storey building, FFS!

They absolutely do - it's nonsensical. They aren't even consistent with what they will allow, so it scares clients into sticking to the rules verbatim - a planner may say a certain rule-break is fine in one meeting, but the heritage guy or urban planner in the next might say it isn't. Depending on the project, the client may not want to rock the boat and will say "screw it, let's stick to the word of the rule" - or they may say "screw it, we'll go to the OMB".
Looks like something here is coming back to life

Noticed that on the way to work on Monday. Wasn't sure if it was new or not though, I don't exactly pay a ton of attention to KFC normally.