True, that viewing experience will be forever altered when watching the films in numerical order. However, I don't care how the number goes, the prequels aren't meant to come first. The OT explains what the Force is and gives other exposition that the PT lacks. The OT was meant to be watched first.
Here's the way a newbie should watch, if you ask me: 4, 5, 1, 2, 3, 6. Each movie brings out something new in that sequencing. Plus, you could see a little more easily and clearly the mirroring of structure and other things from the OT in the PT that way.
Yes, I realize the forum I'm on, a lot of you will probably say the best way to watch the saga is 4, 5, 6 and nothing else. That's cool too, just wanted to toss this out there.