I personally think it's a bit silly to "preserve" the surprise in the prequels. I mean, that's ostensibly what they're all about: explaining how Anakin became Darth Vader. So leaving out that teeny-tiny detail would make them completely devoid of whatever point they were supposed to have. And also... again, they're prequels. Despite what George says, they're designed and structured to be watched after the original movies, so there is no surprise to preserve. Anyone who is watching the prequels should already be extremely grounded in the events of the original trilogy. If you're watching them 1-6, you're doing it wrong. =P