So, info from an internal source at the Delta:
They're positively surprised with the performance of the WestJet YEG-MSP flight, and the amount of passengers on code-sharing flights coming from here.
Delta would like if WestJet were to add more flights.
According to her, Delta has explored the idea of flying some routes from YEG, but WestJet kind of bullied them out, and promised more destinations to connect with Delta's hubs, in exchange for Delta no entering the airport.
The source is reasonably credible, but not enough of an insider that I trust everything she says. But where there's smoke...
I wouldn't be shocked if we got JFK if Atlanta is a success.