I really feel bad about this particular story. All those mechanical stuffs are possibly additional string of bad luck.
However, I do think that FULL FARE ticket means something... at least that is the way the airline trains us to think that by buying a full fare ticket, you are entitled to flexibility and there are some priorities in waitlisting and rebooking. That is why they charge the high fare.
I don't think the poster is over-emphasizing the FULL FARE aspect...
But I really don't recommend a 55 minutes transborder connection at YYZ. It should never be allowed... that is an impossible task... At least an hour and half on today's environment...
Carfield