It's a timing problem. People need to count the ballots, and such, and hence need to work. Work from the time the polls open to the time counting is complete. When it's 7am in Ontario, it's 6 in Winnipeg, 5 in Edmonton, and 4 in Vancouver. It makes it 8am in Halifax and 8:30 in St.John's.
People like the polls to close at 8pm. In Toronto, this would close the polls at 5pm in Vancouver, way to early.
8pm in Vancouver would be 11pm in Toronto, far too late.
9:30pm could be a compromise, and if Toronto, that would be 6:30pm in BC, which is a bit early, but could also be done. This would be 10:30pm in the Atlantic, but, that's a bit late.
If you had the polls close at a different time in the Atlantic, maybe, but then you'd need to like not-count the results, which gets too late for the workers, or just not release the results, which is possible.
Not starting the count till all polls have closed seems like a good idea to me. Fancy some British-style overnight counting?
