I’ve got to agree with vranir’s Dooku point. I think the most ideal edit of TPM would have Dooku instructing the Separatists. Though I don’t know how this could be feasible.
It’d be interesting for sure, and probably stronger for it, but you’re wrestling against far more challenging practical concerns with that particular idea. That said, Christopher Lee has starred in over twelve billion films, so decent AI voice and face models are more reasonable than for some other actors in the series. Best of luck to anyone who fancies picking that idea off the shelf!