I don't feel comfortable answering the question straight-up. British Columbia bought a system that was in some ways actually the most complex, from the point of view of the voter, in the sense of a preferential ballot with a long counting mechanism. I would hope that whatever is proposed, the lead discussion of this does not actually focus on its complexity.
When I say “engineering”, I don't mean that as a pejorative term. I simply refer to the fact that the only self-executing system is first past the post, just in the sense that it guarantees a result: that's all. To go any distance beyond that, because there is almost never a, quote, “natural majority” anywhere anymore, if you're going to have a majoritarian system you need to have some engineering. Then the very idea of proportionality has a whole conceptual framework to it. It presupposes, for one thing, that the thing that is represented is political parties, the very thing that voters claim not to like; and that if you're going to achieve proportionality, in and of itself, but also given the rules of arithmetic, you need to have a set of counting rules that in some sense represents electoral engineering.
I think that is the thing that makes it a tough sell. I understand why people who want to make the sell are concerned about the referendum. Indeed, as Gordon can confirm, the discussion of the sell was important in the B.C. citizens' assembly. They happened to prefer STV anyway, but they concluded that MMP was a tougher sell because of the stuff in it.