The part where Anakin says, “Mercy doesn’t beat an enemy master”, could be an interesting way to integrate a new plot thread into the Prequels, in which Anakin partially turns because he just sees the dark side as stronger.
In my upcoming ROTS edit for example, he won’t show any guilt to having killed Dooku. Not only because I plan on making Anakin a colder character (when he’s using the dark side) but also because he sees it as the efficient thing to do. This way it’s maybe easier to stomach him being willing to murder all the Jedi because as Palpatine says, “When the Jedi learn what has transpired here, they will kill us”. He can’t let Palpatine die because he agrees with Palpatine’s dictatorship and wants the power to cheat death. So he does what needs to be done.