Loving the concept of reordering the film so that it is Darth Vader post-suit that attacks the temple and using the Mcquarrie prototype helmet, but looking down that page at the photos it, the most striking one is the image of the mask without the helmet.
http://www.starwarshelmets.com/2010/SWH_RMQ_Vad10.jpg
It would seem to be the most appropriate approach as the first iteration of the suit should look like it's just had its parts requisitioned from bits of medical tech lying around just to keep Anakin/Darth alive. The sudden appearance of the full Darth Vader suit in EpIII seems awfully convienient that it was just lying around or had been designed and created on the fly. We can easily imagine he refines the mask and adds the helmet later on between films as he grows into his role of the Emperor's apprentice.
It would also echo Anakin's redemption in EpV1 when Luke removes the helmet