The Vader-ish-ness comes about out of necessity. He can't live without the armor. From what I've read on GG, he's chosen to make himself like this. As for ILM being able to pull him off? No sweat. All the armored clones in AOTC are CGI, so I don't think this will be a huge thing for them. I would have liked to seen Asajj Ventress make an appearance on film. I'm assuming she's gong to get whacked by the end of Clone Wars.