More than anything I'd like to see the story progress beyond Dune, into Messiah, and even Children. After that it goes a bit far into the future for a movie to connect as a sequal.
The sound stage work in the miniseries was interesting in the way they made it look, but not really effective in portraying anything more than sand with a few blue gel's in the lights.
I agree that the cast of the 84 one was good. The only thing that REALLY bugged me was that they changed the ending to the point where it didn't make sence, and that put a sour taste in my mouth. Beyond that I think the movie is ok. Were they to mix the two together, a great movie might have been made. The scenery and cast of the first, and the script and direction of the second.
I think the "lost his soul" interpretation is a bit off though. Paul lost his innocence more than anything. He still belived in justice, and law at the end, it was just life had hardened him. I guess it's kind of left at the end of the first book as him being kind of brutal, but if you go on to the next one you see what kind of leader he really is.