Not sure about YQB, but things are difficult in YWG. The new "Deltafication" of the fares means many Error 105s, and very high prices. YWG has about 50/50 mainline / connector. Try to book WBC / First and throw a connector in and good luck trying to get it to work.
It's really hard to stand back and see what's going on with the changeover to Delta. We used to book F to Hawaii once or twice a year through MSP. The F fares are now double and the fares have tons of restrictions. Gone are the nice YUP refundable fares replaced by combo F mainline and restricted connector fares. Don't get me started about what they're doing to the F product MSP-HNL.
I had hoped to see Delta take an aggressive approach to Canada. There is a lot of opportunity here. With northern hubs like SLC, MSP, DTW and JFK why not? Even throw in a few extra ATL frequencies to Canada and give us some options other than Air Canada.
Sorry, didn't really address your question, but the my general sense is that Delta does not see Canada the way NWA did.