ben_danger said:

As much as using other people as "Vaders" to mask Darth Vader's identity - is there not the danger that the big reveal in Episode V would suggest that the dead Anakin Skywalker is not Luke's father, but actually it was the red guy?

Absolutely there is, but I don't see that as a "danger". There are a few possibilities going through your mind when "I am your father" comes up:

He's lying.

Maul/Vader is Luke's father? wtf?

Anakin is actually the Vader in the suit.

Ultimately you get the same thoughts as when you originally saw ESB and heard the reveal. Now, I never really thought preserving the reveal was as important as other people do, simply because in most edits I find that good story ends up being sacrificed to accommodate the reveal, but upon stumbling upon this idea, I feel it's a way we can create both a good story and also preserve the reveal.