So it appears that although
Bay-Adelaide East will be just off Yonge, they will be demolishing a
four storey heritage building on the corner in order to build a narrow podium that extends out to touch Yonge:

From
raptor at
Urban Toronto
There is a pdf floating around indicating that they might replace the facade of the faux-heritage Addition Elle building on the north side with the facade of the heritage building, but that hasn't been confirmed. Otherwise, it's not a huge loss but it doesn't really seem necessary to me. There's nothing particularly prestigious about a Yonge Street address.