Since that's quite an important question, I'm reluctant to give you a definitive response off the top of my head. I was very young at the time of Expo 67, but what struck me was that the two official languages were part of the very atmosphere of the celebrations. You mentioned that the same was true for the July 1st celebrations.
Full bilingualism has always been the case at those celebrations. Matthew Hayday, who is a professor of history at the University of Guelph, has described in his studies how the July 1st celebrations have represented Canada throughout its history. It is fascinating to see how the planning for an event of this kind is an opportunity for the country to reflect on its history, to represent itself in the present and to look to the future. The organization of this kind of event, which seems quite simple, is in fact very important from a symbolic standpoint.
To determine exactly what aspects of the country we will want to present to Canadians and the rest of the world in 2017, I believe we will have to conduct a more in-depth analysis of past celebrations.