Just a little thought experiment:
1) Build a new state of the art soccer stadium at East Harbour. BC Place scale. No more embarrassing temporary stands for major tournaments. Could also host mega concerts like O2/Wembley to replace the need for Rogers Stadium at Downsview. Could spur development of East Harbour as well as adjacent McCleary district.
2) Demolish existing BMO Field to provide more space for redevelopment of supersized Enercare Centre. Meets goal of expanded convention space while leaving room for CNE and other Exhibition Place uses (Coca-Cola Coliseum, Horse Palace, renewed Food Building, QET, etc). Maybe some more hotels, restaurants, etc pop up in west Liberty Village.
3) Extend Ontario Line to Dundas West/Bloor TTC/GO/UPX station to streamline the connection to Pearson.
4) Redevelop MTCC with a mix of AAA Office, Hotels, entertainment and arts uses (new movie theatres to complement TIFF? 70mm IMAX?), smaller event spaces, restaurants, shopping, etc decked over the tracks to take advantage of proximity to Rogers Centre and CN Tower.
Obviously its a pipe dream and maybe wasting a lot of embedded carbon. But no lake fill. Win-win-win?