In an unusual move, the full version of a report (almost a 70MB PDF) of a design charrette on entrance identification is available on the TTC’s report website. If you want it, grab it while it’s still there as this situation may not be permanent.
I will add comments here after I have a chance to digest it.
Update 1: I got all the way down to the last page after the file downloaded, and there was a pair of photos of the existing sign at Osgoode Station and a proposed replacement. The “new” one looked terribly familiar.
A quick visit to the City Archives confirmed my worst fears:
Here is the original entrance on the south side of Bloor east of Yonge.
The old signs used the shape of the TTC flying keystone (the wings were added for the “Rapid Transit” image to the original 1921 design), and this was simplified to make the signs cheaper to build and maintain by the time the Bloor line opened in 1966. The main differences between the 1954 and the 2008 versions are the use of the “modern” TTC colours in 2008, and the absence of the word “SUBWAY” across the wings of the sign.
Update 2: As a public service, I have put a condensed version (1.3MB) of the TTC’s file on my site.