I haven't been an avid follower of Bendis' Avengers in quite some time, but I read that Wonder Man more or less said that he was just a Wanda-construct and then disappeared. So the implication is that Wanda never had the power to bring people back from the dead, and was instead just making walking/talking facsmililies. So if this is true of Wonder Man (who Wanda "resurrected"), shouldn't it also be true of Hawkeye?
Never believe the word of a man with a known mental condition and a problem with twisting the truth into what he wants it to be. As Children's Crusade established, those revived by Wanda are pretty much real people, as Jack of Hearts was enough of himself to beg Wanda not to do this. Simon's just crazy, driven that way by his powers again.