The Investor Day presentation does open up the possibilities...
Looking at the Transborder O&D figures (again) every single YVR route > 30,000 passengers increased between 2014-2016 and in some cases substantially. In fact you have to go all the way down to BUF-YVR to find a route that decreased between 2014 and 2016.
The exact opposite happened for YYC and YEG routes. Except for YYC-SEA, YYC-BOS and YYC-PDX... every other single route > 30,000 pax decreased.
Since 2016, YVR Transborder ops have increased almost another 1,000,000. Obviously some of that would be connecting traffic but some of that would be O&D market growth.
With the economics of the A220 ("unparalleled operating economics") certainly some new routes will pop up. Another game changer plane for NA ops. Just like the Dreamliner has been for long-haul ops for AC at YVR.
Based on the numbers I would say AC will start YVR to IAD, MCO, IAH and MIA/FLL (either one) would most likely get the nod. Some of these have been identified as possible routes in the Investor Day 2019 presentation already. I could also see some current routes such as ORD and DFW switched to mainline 220s. Once you start going further down the list things still get a bit more iffy. No we won't be seeing nonstop flights to Kansas City, Pittsburgh, Omaha or Austin (yet).
This is based on market numbers and not just a whine for more routes based on some sort of inferiority complex.
https://www150.statcan.gc.ca/n1/daily-quotidien/170816/dq170816b-cansim-eng.htm