I may have missed this in one of your posts, but have you notified Air Canada that you've filed an official complaint? Replying that you've done so may prompt them to offer better compensation (or could cause them to issue no further comment pending the outcome of the investigation).

Based on the air pressurization story, it appears to me that AC would rather fight this than pay out. If they feel that there is something the chain of events that is extraordinary (and they can demonstrate this), they will spend a bunch of money to prove so. It wouldn't be just you that they have to pay, but all of the other pax on the plane. Plus, if they can get a ruling that this was an extraordinary circumstance, they'll have precedence for any similar delays and can save themselves a bunch of money in the future.

I wouldn't worry too much about suing. I'd wait to see what the response is from your official complaint. If it is in your favour, then pursue it with AC customer service. If not, you may as well drop things...