Oh yea, on the animation front I 100% agree with that, especially for the 1st part. It's a shame WIT didn't want to do it anymore. Same for Sawano not doing the music anymore. However, if they didn't split it up, I think it would've suffered worse. For example, part 2 was already a step up from part 1 in terms of animation. But that's only the animation. The story would've suffered the most if they rushed.

Of course, in the ideal world they would've done neither and planned their projects properly to give them enough time to finish it in 1 go.