You can still submit ideas - the deadline is April 29th, 2016.
Of course, being a westerner, I'd like to see that the Gateway (and the Hall) reflects all of Canada, especially the west and the north. The criteria seem to make that a little difficult, but use your imagination and knowledge of Canada and submit your ideas now.
Here are the criteria:
Landmarks are visually recognizable places or locations in Canada still standing today that speak to events of the past. Examples: Citadel Hill in Halifax or Habitat 67 in Montréal. Please do not include landmarks that no longer exist or historical photographs.
Symbols represent aspects of Canadian life or identity. For example: the beaver on the nickel (as opposed to a picture of a beaver in a lake) or the maple leaf from the flag. Keep in mind this category is not about geography or natural history as such (it therefore excludes images of natural landscapes such as Niagara Falls or Banff). Nor is it about commercial logos or trademarks.
In this category we’re looking for images of Canadians doing activities typically associated with Canada. For example: kids playing hockey or pow wow dancers. This category does not include Canadian personalities or represent any recognizable individual. It could however include monuments erected in memory of specific individuals, such as the Terry Fox monument in Thunder Bay."
Why would I quibble about the criteria?
The west and the north have few 'old' built landmarks, But I'm thinking right now of Nisga’a Memorial Lava Bed Park and the Alaska Highway, and Nanaimo's Bastion though it was an HBC (commercial) building. First, it represents British Columbia's fur trading and mining beginnings, but also, in 1909 it served as a symbol of BC at the Alaska-Yukon-Pacific Exposition and could symbolize BC's historical place in the Pacific Northwest of North American and then and now in the world's Pacific area.
And as for symbols, for instance, why think of Canada's history without the Hudson's Bay Company? The HBC seal seems an obvious choice to me, but it is commercial. So would be an HBC blanket, I suppose.
And Canadians doing Canadian things- well, there's lots of hockey in the west - and soccer too, what else, skiing, fishing, whale researching, still some lumbering, mining, no maple syruping but lots of growing grapes and drinking wine though!
And walking on the Seawall where I live. Maybe choose Vancouver's Girl in a Wetsuit?
And as for monuments to people, my first choices would be something to do with the Northwest Rebellions and the Pauline Johnson Memorial in Stanley Park. (Surely Stanley Park itself should qualify as a landmark.) And please! there are Terry Fox monuments in Canada, but none like this one in Vancouver.