I haven't travelled since April and haven't flown from the international wing of YUL since last year. I just flew YUL-DUB and I was gobsmacked. I've never, not once in the last 15 years of flying out of YUL internationally, seen the airport so packed. It was absolutely heaving. It was actually kind of difficult to make it through the terminal, there were multiple gates where the crowds of people lining up to board were blocking the passageway. The lineup for the National Bank lounge was also blocking the terminal.
There are a lot more restaurants open than I recall even pre-pandemic and every restaurant had a line to get in or order. A lot of the congestion was caused by those restaurants narrowing the terminal but then I wouldn't want fewer restaurants either. With the exception of the duty free shop it wasn't frivolous shops fleecing tourists blocking the way. It really was just that crowded.
Fwiw my flight left early and landed early. The staff boarded by zone strictly and made multiple announcements asking people for later zones to wait until they finished previous zones. They were on top of everything both at the gate and on the plane. I don't think I've ever seen an AC crew so on the ball about everything before.
Not every flight on the board was on time but I didn't see any egregious delays and the gates all seemed to be staffed and people seemed to be ready to board.