I think that part of the problem is that people view wayfinding as a be-all, end-all - one single piece must do everything. That's a great way to overload it and make it incomprehensible. There's no reason why there can't be a more simplified approach is used, with different pieces of wayfinding doing different - and appropriate - things.
I'm even more cynical - the Great GTA Wayfinding Pogrom is the result of ML recruiting too many people with ivory tower mentalities (and insufficient practical experience. Talking at a system level is not always a substitute for knowing how things actually work.
(As a specific example, some of the wayfinding at track level in Union Station is neither lighted nor kept clean.... putting a new sign up in perfect Metrolinx font is pointless if the font is white-on-black and allowed to collect grime and soot from diesel exhaust and erected in a dim shadowed recess in the roof. The truly excellent transit professional would engage a janitor and an electrician, not a graphic designer or a head office signage wonk)
Add to that the opportunity for the ML bureaucracy to drive this kind of practice into other peoples' turf, thereby empire building.....certainly some properties may be set in their ways, but wayfinding is not the place to correct that.