En Sabah Nur
The First
Why was this changed?

The way Anakin blinded Dooku and switched hands mid-duel was coldThat should have stayed in the movie tbh.
I've mentioned in other threads that I like how the final duel with Dooku mirrors Luke's decision to spare Vader in Return of the Jedi. In both cases a Skywalker was holding the big badguy that previously cut his hand off dead to rights. Anakin gave into his vengeance while Luke spared his opponent.
The Dooku fight was lowkey better than the Anakin/Obi-Wan duel at the end IMO.