I think it has to be a mix of everything that has been proposed...
Ground level: A true public living room called "Stephen Avenue Commons"
Use the arcade edge as Calgary’s weather-protected promenade and fill that strip with uses that create “reasons to go” beyond shopping:
An experimental pop-up food hall + micro-retail (Leonard-like variety, but indoors): multiple small, more affordable spaces. You wouldn't be competing with anyone else downtown.
Experience-focused anchors at the corners (cafe; bar; showcase space for satellite post-secondary campus (read on))
A daily-programmed event spine: markets, mini-concerts, winter festival tie-ins, Indigenous makers weekends
Mid-levels (2–4): Education, innovation (Platform-like), and culture
Use these floors to drive daytime foot traffic:
Isn't CBE looking for more learning spaces? Could get them involved or could always go with a post-secondary satellite campus like AUA, SAIT or continuing education like Bow Valley College, can connect them with innovators in an incubation space
You can leverage those campuses for workforce training (digital skills, trades-adjacent programs, newcomer employment bridging)
Find education streams that could tie into the showcase space (exhibits, demos, “see what we're doing”)
Upper levels (5–6, and you could do something on the roof): Housing that brings people to the property at night
Use a couple floors for residential or even a hotel:
Use the large floor plate to your advantage, create a central space (with light wells, similar to what Glenbow just did) that shrinks the floor plate left over for mixed-income rentals
You could even include a student housing component or boutique hotel.
Add in a top floor or rooftop restaurant and event space (weddings, conferences, civic receptions), could also incorporate a rooftop garden (greenhouse-style), there would be some cool views of the city year-round
If you can break the floors and floor plate up and use incremental leasing, you don't need to eat an elephant in one bite. It will have to be a public–private partnership, especially if you're doing micro-retail and a hotel. It is important to not try and do everything right away, this can be a phased plan (so it doesn’t sit empty for years as the refined plan comes together)
Phase 0 (0–6 months): “In the meantime use” activation
Pop-ups (like River Hall but indoors (next winter): markets, art installations, social games space), it doesn't have to cost a lot but will get people in the door and using the space while the subsequent phases are refined.
Phase 1: Ground level
Get the ground-level “Commons” open first (fastest visible win).
Phase 2: Education floors
Bring in the weekday engine and these space could require less work than the housing or hotel.
Phase 3: Housing/hotel floors and rooftop
Finish with the components that will take the most work, by this time the building has momentum, and people will want to live or stay here.