I think so - we are the wealthiest major city in the country yet we (arguably) have the worst stadium.
A right-sized facility designed for football, soccer, and rugby would be an asset to the city and enable hosting events that currently bypass the city like national team soccer matches, rugby sevens...perhaps a future Winter Olympics.
CFL, Soccer, and rugby? I thought we've learned from the experiences of mid-century multi-purpose stadiums in the US that shoe-horning different uses into a facility intended to do everything often results in a facility that does everything adequately but nothing well.
In seriousness, the mix of uses is what determines whether the space makes sense. All the rectangular pitches work well together since they're similar shape and size.
The rodeo could be handled inside a football stadium, either just have it full-arena as in the Houston pictures above or move in an 'infield' type facility as part of the transition to shrink the space and put more seats closer to the action. The chuckwagon races are the challenge, assuming they don't change in any way (although the chuckwagon rules change every few years). One option is to keep the track and during Stampede slide the end zone bleachers away to open up a space at both ends of the stadium for the chucks to run through onto/off the rest of the track, and spectators just have to watch the (most boring) middle part on the jumbotron. They could also do a modified entirely in-arena version like in Houston.
Or, get rid of the chucks; entirely; they could set up rodeo on one end of the stadium, the evening show on the other, and then have a more elaborate grandstand stage that doesn't have to move every night and better sightlines to both events with similar capacities; both events could also benefit from better concessions, jumbotron, etc. If it makes traditionalists feel better, they could still euthanize a horse or two every year to keep up traditions.
The benefit of a multi use facility is more return on the same investment; rather than two bad facilities that get used 10 times a year, it makes sense to have a better one that gets used 20+ times.