I think the idea of a deserter Jedi other than Anakin could have been interesting, but they didn't play with the duality nearly as much as they could have.
The guy does have the distinction ONE Sith who doesn't go absolute batsh*t when he duels. At least, in comparison to his cohorts.
You know, the prequel trilogy had too many characters. Especially antagonists. Had Dooku been the only one, apart from Sidious, this might be a different conversation.