Bingowings said:

I have no idea if it is possible but if after "I don't believe you" Dooku said something like "That is why you will lose" (which sounds like a classic bad guy line but in this context isn't).

Not only would it mirror Yoda's line to Luke in ESB it would also show how prescient Dooku is.

Ultimately the Jedi do lose because the Dark Lord is controlling the Senate and they are taking sides instead of investigating his claims.

I like the idea Bingo. Did you see SSWR's version of this scene? As Dooku leaves, he says "we will see" :)