Let me add my own feelings of disappointment. I've been planning a trip to Calgary for the past 18 months and only last week began the process of inking Autumn dates into the 2018 diary. I'm now kicking myself for not getting my act together sooner.
TBH, I don't much relish the idea of booking a connecting route via DFW as apart from the extra travel time, the long DFW-YYC flight in a regional jet is off putting. This situation highlights just how thinly Calgary is served by oneworld.