My issue with these buildings is that they are so large that repurposing them is near impossible. The Enercare Centre itself could fit the BMO Field, Air Canada Centre and SkyDome within its footprint, and there would still be plenty of room to spare. It has a perimeter of nearly 2 kilometres! I'd wager that Enercare Centre has a bigger ground-level footprint than any other building in Old Toronto. The facility is a massive bunker, that makes accessing Exhibition Place by foot tremendously difficult. It's certainly a facility that was designed with automobiles, not people, in mind.
I understand the desire for historical preservation, but I cannot see any proper revitiaziation of Exhibition Place keeping this building intact. Now I don't even know if this building is considered architecturally significant (it was built only 24 years ago), but if it is, I think the best option would be to demolish most of the building to make Exhibition Place more pedestrian accessible, while retaining the most significant parts for historical preservation.
Also, when I used to work at Exhibition, this building was virtually empty 99% of the time, which is no surprise given its immense size. It's a massively under-utilized facility.
I could see us keeping all the other buildings, but something needs to be done about the Enercare building. It is completely out of place in an urban core