I agree that duping is lame and should be banned/punished, but I'm also smart enough to know that there's nothing they can realistically do about it. Either they spend all their time on security and then the game play suffers, or they give you ways to avoid duper/cheater (single player, ability to kick players in a game you hose). They just can't do both. If they make single player too difficult or not worth playing then I won't buy the new one, but whether or not they focus too much of their time trying to prevent people from being jag-wagons online (which is impossible) won't directly affect my decision.
It's not like this is a new problem. It's been going on since the first Diablo. Claiming you won't buy the new game because of a 15 year old problem isn't going to do any good.
I also agree that the poll sucks. There are no good options.