Affordable Housing doesn't make any sense here. They need to make money on this place so if there's any residential it should be extreme-luxury condos. If they go that route they could follow a similar plan that Avant did: Some Residential; Some Hotel; some Office; some Retail.

Starting from the top: Take the highest 2 floors and make it banquet space and public restaurant again. The next 10 floors down could be luxury condos... 4 to 6 huge apartments per floor possibly selling for ~ 1 million each. The next 10 floors below that could be hotel rooms. The 14 floors below that would remain office space (upgraded to prime class-A space). Then the 2 floors on the ground would be lobby space with a restaurant and some retail. The outer walls of the plaza could be opened up as street retail shops facing Main St and Canalside. This would make the building part of all the new developments nearby. Another possibility is relocating the Seneca St metro stop to the base of the tower and include a modern metro station in the design. The first-floor retail could be integrated into the metro station. Imagine having the train stop right at the ground floor of your apartment/office/hotel-room... pretty cool.