I'm not so worried about the connection time at YYZ as i am about the aircraft being delayed and our departure time from YYZ becoming 2:00 in the morning.
Browsing through AC's schedule i see a BUD-YYZ flight arriving at 16:30, an ATH-YYZ flight arriving at 17:00 and a TXL-YYZ flight arriving at 18:00. There are a couple of Dublin flights arriving earlier that day as well. I'm assuming that 5.5 hours is more than enough to turnaround a 767 but i do wonder why AC changed the YYZ-TXL flight departure time from 22:30 to 23:30. My first assumption is that the time between the YYZ-TXL leg and the leg prior is short so they bumped the flight to 23:30. I don't know for whom a 23:30 departure time would be advantageous.