As beyond_elechan says, people write in different ways, so to clearly state that a writer should ignore the promptings of the characters and stick to a pre-planned outline, come what may, is very bad advice.
I have no problem with people who say, "Here's how I do it. It works for me, why not give it a try?" (John Braine does that in his How to Write a Novel, which as it happens is the total opposite of Butcher's Plan Everything Up Front method.) But those who say, "This is how you must do it," are dangerous to new writers. To be fair, Butcher does give a small disclaimer at the very beginning, but it's overwhelmed by the rigid instructions that follow.
beyond_elechan's post was strangely well-timed with regard to my own WIP too because I had just come to the conclusion that I need to ditch a big chunk of the beginning of Necessary Evil -- and it's all the part that I worked out consciously and researched most carefully! I'll be going right back to my much earlier idea of having an informal unit of mounted scouts, which was the intuitive idea that I subsequently decided (by thinking things through rationally) could be done better. I was wrong. In this case, intuition outperformed rational thought by a considerable margin. As anghara says in her latest post, a few darlings will have to die, but the story will get going much sooner. The whole infantry/learning to use muskets thing wasn't working and it started story strands that ultimately went nowhere.
So my writing revelation for the week had been "Trust Your Gut!" which is completely the opposite to Butcher's advice. :)
Having said that, and just to show that there are little lessons and bits of useful information that can be found in even the crappiest of crap advice if you cherry pick, the bit about the Big Middle was reassuring. Because in the very very original version of the WIP (back when I was about 15 and it was called The Land Beyond the sea), the big battle was the climax that came at the end. More recently it's been moved to the middle and has never felt comfortable there, but now Butcher has said that it's acceptable to have a big climax in the middle, I feel much happier about it and feeling happier will help me get a better grip on how to structure the novel.