Admiral M wrote:
not to mention that Obi Wan eventually defeated him.
*cough*something about a duel on the Death Star*cough*cough*
Thematically, it makes sense for Dooku to die early, especially with Anakin essentially killing him in Cold Blood. It parallels Luke having the opportunity to do the same to Vader. The movie is primarily about Anakin's conversion to the Dark Side and it makes sense not to prolong this necessary step longer than they have to.