I like this idea.
My fear is that if we get politicians to re-draft a new constitution, and the people vote on it, will we get a worse one than we already have?
Will God be dropped from the preamble?
Will the public vote in a right to abortion?
And I don't see Quebec approving any constitution. Especially any constitution that does not address typical Quebec demands.
As for an amending formula, I think there should be a referendum option.
If 75% +1 of Canadian voters (with a minimum participation rate!) vote for an amendment, it should be adopted, with the proviso, that certain rights never be suppressed, such as the right to life. You can't vote to legalize killing other people.
And I'm not even thinking of abortion and euthanasia. Given the propensity for humanity to adopt killing to solve its problems, we should cut to the case and make sure nobody ever votes away the right to life.
Because I don't trust the culture.
I like the idea of constitutional change, but I don't think it's workable. The Americans and British were very much united. I don't think Canadians are.