The first half should be the beginning of the second movie, the second half should be the last half of the third movie, and there should be a whole movie in-between exploring Anakin’s turn, having him gradually be seduced by the dark side via the usage of Sith holocrons or something. Have him lose himself more and more in the war. Then have him turn.
Yes. Plus you need two full movies to develop a really close bond with Obi Wan, otherwise what’s the point of wading through all that lava in Episode 3. I really wanted ROTS to break my heart. But instead it just sort of made me mildly sad for a few seconds.