Vancouver Convention Centre Expansion Project | Completed

[red-paladin]

The largest centres on that list are presumably intended to host multiple giant and small sized conventions / events at the same time.
With our current space, there are probably few conventions that would be 'too big' for the entire convention centre (new and old combined) to host.
Also, we do have BC Place, SFU grounds, and lots of other places that host small conventions too, and we don't have 10 million people in the city. So I think the size envy thing is a little over blown.
If convention space was really at a premium in the future, it would be better to build more convention centres in Burnaby, Surrey and Richmond than to have one giant building that takes up all of coal harbour. At least then, there would be a lot of flexibility, and different locations at different price rates.
Like some previous comments noted, some conventions are completely inward focused events, and could really be held quite nicely in a giant building with lots of big rooms in the desert (like las vegas), and others benefit greatly from a fantastic location in the middle of the waterfront.