Post secondary has somewhat unique circulation needs. You want all student focused things which are time sensitive accessible by stairs. There is a reason the new buildings at UCalgary are all 4 floors, and the fourth floor (in general) have minimal to no instruction space. Big, low floorplates are good. Anything above that you can't usefully use for grad students and offices you convert to residential. In my mind, Shell stood out, as did Gulf Canada Square, the entire block just east of Nexen.
The biggest barrier isn't space though. Space is cheap compared to operating cost. quarter of a million square feet of post secondary you're talking like $60 million a year in operating costs. Bow Valley College has $120 million annual operating costs.
Until the province is willing to step up and fund a generational expansion of post-secondary, it won't happen. A little more than a year ago a very large investment was killed by the province before it was announced, but after it had almost all the approvals it needed.