You're right that not many people seem to be talking about it - guess there's other big news happening at the moment which is keep the referendum out of the headlines. I won't be surprised if many of the people who vote are those who are determined to keep the status quo (first past the post) - apathy prevents change!
I agree, except that those most likely to make the effort are going to be those who want change, which I think gives pro-AV supporters the edge, even if most of them have no idea how to calculate the results! I think there should have been a minimum turnout requirement - if hardly anyone votes then a huge change will go through without anyone realising what's happened.
Definitely - like you say, it's pointless having such a monumental change if hardly anyone's been informed properly about exactly what's happening. Not sure the pro-AV voters are much more likely to turn out than the anti-AV voters though - could be even stevens among the tiny numbers of people from each side!