That is true. Jedi, at least, believe in some kind of life after death. For a Sith, who's goal is only power, death is truly the end. I suspect Palpatine might not have a problem begging for his life, either (he might have already, depending on if you view his begging in ROTS to be genuine) You see it all in his eyes, though. Christopher Lee is such a great actor that you can see him begging Palpatine without saying a word. In that way, he still managed to go out like a badass. But I also agree with what MercenaryAce said, about a small part of Dooku still being a Jedi (seriously, TCW, Dooku is a much more complex character than you seem to want to show; he's far from a mwahahahahahah villain). He had a much more strict system of honor and dueling etiquette, something the Sith seem to only have when it suits them.