One of the other things that I hadn't considered was that while the bulk of all three films were filmed concurrently, they had the release schedule after the first one to react to criticisms, do re-edits and re-shoots in places. She suggests that Two Towers is kind of the messiest of the trilogy because they production team were reacting to Fellowship being out which was their first criticism and so they were heavier handed in their choices than they should have been, which I can kind of see in that film.
And because no decisions are made in a vacuum, they had knock on effects elsewhere. It's a good assessment and quite interesting.