I remember the rationale for replacing the street signs as being that they cost approximately $50 less than the old Acorn signs and the Clearview font is easier to read, according to the Manual of Uniform Traffic Control Devices.
The second justification makes some sense: if street signs need replacing, you might as well make it in a more legible font (this despite the fact that the old street signs were perfectly legible - especially for pedestrians - and did not indicate a hazard or risk for road users like 'Watch for Children' or something like that).
The first reason is pretty shortsighted. Even if 10,000 signs get replaced a year (impossible), for an added cost of $500,000, it's well worth it. Those old signs not only had character but they were iconic to Toronto. In this city that desperately tries to spend money to market itself and find things that are unique about itself to broadcast to the world, it takes the things that actually provide symbolism and meaning and throws them in the trash.
I would have been much more supportive if they would have kept on making the old (not the new, cartoony flat versions) acorn signs but with Clearview lettering than if they would have replaced them with these clinical blue signs.