I attended this ultimate, postponed display last August, which celebrated Luso's victory (not mentionned in last night episode of Pyros). I did a review of this 35-minute show on this forum:
http://www.montreal-fireworks.com/forum/index.php?action=vthread&forum =4&topic=2587
Strangely, I don't remember (and I didn't report) about the interruption caused by a shell burst into a mortar, tackled in "Pyros". But for sure, such episodes make me realize challenges pyrotechnicians have to take up (even during a display) that we don't even suspect as a viewer. Along the same line, last week episode featured some material from the British display at La Ronde in 2012; a few minutes following the start of the show, the technical director Paul Csukassy got a phone call that two people were still on the road between the main firing ramps! What a stress!
Back to the Quebec competition, the water fall was, for sure, a major problem. But I don't believe it caused the cancellation of the event. More important, I believe, is the competition from other nightime (and free) entertainment opportunities in Quebec City since 2008, especially Le Moulin à images and the outdoor performances of Cirque du Soleil, both centrally located in the heart of the city.
The Montreal competition has also suffered, I think, of the increasing competition between summer events which didn't exist or were not as popular in 1985 (Jazz, Francofolies, Juste pour rire, etc.). I suppose the larger number of people living in the Montreal area, the presence of more corporate customers, and the "support" of an amusement park to add to the fireworks event have helped to keep the Montreal competition alive.
Finally, we have to note that Canadian fireworks festival are challenged these years. The Vancouver competition has been cancelled in 2011, then bring back alive at the last minute. A similar pattern now happens in Quebec City.
Fred