That's what it is. It's a billboard canvas with retail behind it. The more of the building that gets covered in higher quality signs, the better it'll get. The new corner display is a huge improvement in that direction, covering up a large expanse of grey cladding and consolidating a lot of the clutter of the signs it replaces with one high quality display. Replacing the vertical billboard with something creative like the Coca Cola sign in Times Square would be another good move. Then consolidating the remaining signs on the eastern facade into a single long waving "ribbon" display like
@P23 suggested would complete the look.
A movie theatre and restaurants is the perfect use for this building. Delving further into entertainment, it would be fantastic if they returned to the original concept for the building of putting rides on the roof. Even though Disney dropped out, the anchors for the roller coaster and at least a part of the infrastructure for a drop zone like ride is also there (the cylindrical pillar on the east side of the building). Cineplex has been expanding into experiences like these with Rec Room. The Winners (former FutureShop) floor was originally intended for this purpose.
I think that as the area grows up, capitalistic forces will improve the quality of the venues around the square. Those forces are already working, upgrading the crappy little screen there before into a high quality display to compete with the Eaton Centre's much larger super HD display. Rogers is taking over Forever 21 and the display over Shoppers was also upgraded. I don't think the area will be recognizable in 10 years.