A. This new scene with the Emperor has the fully revealed face, like the original, that looks much closer to ROTJ Emperor.
B. Same voice, instead of different.
C. The dialogue is not more revealing, in my opinion. If someone is watching the Classic Trilogy for the first time before the Prequal Trilogy on the DVD here, the line could very easily be seen from the point of view of you would get from Obi in the hovel. My guess would be the line with Vader would thought of like, "How is that possible?".........I killed him years ago........you see what I mean?
D. For those who say, well he was obsessed with Skywalker, so why does he ask. There is C. and also maybe Vader thinks this is the son of another Skywalker, not Anakin but maybe his brother or something. Possibly it's Anakin's nephew or something like that. Another possibilty is he is lying. Or if you watch the prequals first and don't know Anakin is Vader, maybe Vader asked it because Jedi are not supposed to have children.
To Luke Skywalker, I would say it is dependent upon how much Obi-Wan is focusing to show his identity to Luke. When he is talking like a person, he looks more real. However when he wants simply to be seen only, you can see more of the force in him. Assuming he wants to be seen, considering he only talks at first in Yoda' Hut after his reveal physically on Hoth. Also I think this explanation is needed for the OT as well, he looks less blue in shots when he is talking and his blueness varies just in general between ESB and ROTJ.
To bad_karma24, I would say that both the old and new Emperor scenes have Emperor's who move very little, they are both pretty stationary. The biggest difference to me was the fact that the old Emperor seems to be blinking more.
And those are the DJR Opinions for this Post.
Edit: Forgot to say to HotRod, I share your feelings, I can't wait either. I am downloading the rips right now to hold me over until the DVD's are on sell.