I'll quickly throw some roads, highways and infrastructure talk in here to justify the rest of this post... By combining facilities you really start to justify the infrastructure spending in Victoria Park for the new Victoria Park Stampede station, 17th Ave extension, 5th Street SE underpass, Green Line LRT, Stampede Trail, Riverwalk continuation along the Elbow River, 25th Ave and Macleod Trail intersection upgrades, and (eventual) Erlton Stampede station update. Along with whatever else this could spur. Suddenly by combining facilities the large infrastructure investment in the area starts to have that much payoff... Now on to the current topic.
The Grandstand has a lot of potential as the home of the Stampeders. The problem is that its just too awkward of a fit as its built. The answer to the square peg round hole problems of getting the Stampeders down to C+E is completely rebuilding the Grandstand and infield. With a blank slate approach you could really do something special. The grandstand is pretty outdated, as a 10-day facility it shouldn't have much if any money sunk into it, as a 10-day plus Stampeders, and other events maybe stretching its use suddenly you have the opportunity to do something special:
Imagine a stadium or as it would likely be dubbed Large Events Centre, capacity is about 30,000 (plus standing room) but it can be expanded to 40,000 for extra large events. There's a 18,000-20,000 seat grandstand on the west side and 8,000-10,000 seat smaller grandstand on the east side. Sprinkle in the standing room areas that would connect the two grandstands and you get to 30,000 pretty easily. I think that's a good number for the Stampeders and Stampede, if you want to add capacity, simply build some bleachers in the standing room areas. Shrinking the length of the west grandstand you'd likely be forced to build a bit higher to maintain the current Grandstand capacity, not a big deal. You could building a bigger east grandstand than what's there now because if you've ever been to the chucks and sat low on the grandstand or in the infield you end up watching the backstretch on a screen anyways.
For Stampede, you bring in a bunch of dirt to cover the now slightly-sunken field to complete your track and infield. Remove the standing room areas that connect the two grandstands and the field-level suites (I'll get to those later), then you're ready to go.
For the Stampeders or Soccer, Rugby, and other events including open community use, the biggest change compared to Stampede configuration would be the standing room areas connecting the two grandstands (think Pilsner patio like they have at Mosaic) that can be removed or added to for extra capacity (add bleachers for Grey Cup) and where the chutes are for Stampede, you can add some field-level suites that are slightly-raised above the players bench.
The build-out would be pretty simple, one summer after Stampede, demolish the west grandstand and build the new west grandstand, or as much of it as you can before the next year's Stampede. After that greatest outdoor show on earth demolish the east in-field seating and build the new east grandstand. There would be a couple odd years of the Rodeo, Chucks, and Grandstand show that take place in either half built or temporary bleachers but once its done you've got something that works for both primary uses. And between the big events a large open sports field could pretty easily find some uses by the C+E. Not to mention I'm sure CSEC wouldn't mind combining offices somewhere in Victoria Park with the Stampede, the only office space you'd need at each facility would be the operators and direct team staff. Add a football/rugby/soccer practice field and community rink to Victoria Park next to the CSEC/Stampede offices and suddenly you're filling in a lot land in Victoria Park.