Janus Marius
Plo Koon Rulez!
Really, I think the whole idea about the Chosen One prophecy detracts from the overall good things that come from the films. In any series where a similar type hero is used (Such as the horrible Matrix, or Harry Potter, for example), the storyline becomes more and more about the hero's destiny and less and less about other issues the series raises. In the case of the Matrix, the ideals of freedom, control, and survival became absolutely moot by the last movie (Which I still regret watching). Likewise, Harry Potter's all about... Well, Harry Potter. That's probably the intent, and it's not badly executed. But there's no real depth to the great and imaginative characters, background story, and depth when you make all this great stuff and then make it all about one person's destiny. Just undermines the effort, IMO.
And the Sith after Sidious were pretty much pretenders, but the same could be said for those after the Hyperspace War, or the Jedi Civil war, etc. The Sith as a collective have been reshaped many many times.