YEG has a lot of things going for it and some things going against it. Looking at the landscape of the Canadian market population growth is essential but a market our size being the 5th largest airport by passengers flown is a tough hill to climb.
It doesn't mean there aren't opportunities or they haven't tried things. Flair setting up shop with their HQ was an outside the box opportunity, unfortunately things haven't gone so well for Flair. YEG is an important Westjet market, maybe their 3rd most important base. In ideal circumstances, with Westjet so fortressy you would see AC utilitize YEG as an important interior focus city/hub as American carriers have in different markets like Salt Lake City (DL) or Phoenix (AA), but they have a history in Calgary and have chosen more to draw down prairie flying than operate with much of a hub between YVR and YYZ. Porter could be a future target, they've stated YVR might be their first western hub but nothing written in stone if they became a true national carrier and YEG played their cards right.
Working against YEG:
Geography - Being north means backtracking on connections heading south in many circumstances.
Tourism - Mountains are a big trip generator and while Jasper could be much better marketed and accessed, Jasper isn't as interested in becoming what Canmore Banff is and will never be as convenient unless a much better train service or some sort of regional flying became a possibility into say Hinton.
Canadian Dollar - Canadian airlines are better positioned to deal with the weak CAD vs. USD so while it would be ideal to get more DL, AA, UA flying to improve our transborder flying, those flights aren't as lucrative for those airlines compared to flying more domestic route options.
Working for YEG:
Geography - Being isolated with Calgary being the only reasonable place to drive means flying is best option for a large number of trips. Also need to better leverage the gateway to the north, we see too many flights overfly YEG but could be taking in more of the Northern AB,BC, & territories flying.
Population - We are keeping pace with Calgary and continued growth makes it harder for YEG to be ignored by airlines over time.
Capacity - Travelers that use YEG be it as their origin/destination or for connections, appreciate the experience for the most part and that helps make the case for more at YEG.
It's easy to fall into the trap of "just one more" but, I think passenger numbers we are a little too far behind Calgary and a little not far enough ahead of Ottawa. Would be quite satisfied though if we end up getting ORD, Texas (DFW or IAH), & London (LGW or LHR).