Count Dukuu in Revenge of the Sith. Yoda couldn't even beat him in AOTC yet Anikin can easily do it in the third. Yeah so he turns into Darth Vader, but still.
Yeah, I'd second being a bit disappointed by the speed of Dooku's death. They crammed a bit too much into RotS IMO. I totally understand the reasons for introducing Greivous as a cyborg character, but I'm not convinced his role had to be so large. Some of what he did could have been given to Dooku instead.
But given the size of his role, you could probably also include Greivous in the topic's list. And maybe even Palpatine.