The interior of the Crowne Plaza has had a complete rebuild and is apparently very nice (although I have not seen this in person).
I can't imagine them tearing it down in any redevelopment of the Aquillini Block.
I can see them recladding the tower to make it more fresh and modern in appearance, and possibly expanding the hotel, perhaps by building a second tower.
JHikka is correct. I think the eventual redevelopment of this block will include a number of components, expanded hotel (maybe with convention facilities), bars, restaurants, retail, enclosed parking and perhaps even a residential tower.
Personally, I have a hunch there will not be a commercial office component. I kinda think that if there is any nearby expansion in this regard, it will be at 1222 Main. I still believe that Crombie has something up it's sleeve for the entire former Terminal Plaza Complex - something along the lines of what I included in my fanciful sketch from earlier this year.........