So I could understand why AC would not wanna show upgrade priorities on a screen like UA does:
1) Need $$ to invest in the screen and the computers to drive the data to the screen.
2) Potential privacy reasons.

So, instead, I'd like to suggest that Air Canada adds a feature to the existing Air Canada app or website that allows people to look up their gate-upgrade queue/rank using their confirmation number and aeroplan number, after check in.

It will also be good show show the upgrade queue / rank during OLCI when offered last-minute-upgrades.