Hypothetical uses for Rideau street's Hudon's Bay building

Again, hypothetical as the building might just be owned by CF as a part of Rideau Center or something, but putting this aside for a second, the building is quite massive and central.

What are some ideas you think would be a good use of the space (either as is, or renovated). I don't see a single retailer taking up the 4 floors or whatever as is currently the case, but dividing it into several stores is probably an option. Aside from simply more mall space though, anything else?