Maybe this is unfair of me, but it's really difficult for me not to get frustrated with the argument that some aspect of whatever creative project should be "100% nailed down" before X/Y/Z is even started. Like. It just makes me feel like they don't get how a lot of creative projects work.
I've been part of, and lead, a ton of projects over the decades, some of them creative, some technical, some both. One of the main reasons I'm saying what I'm saying now is that I've come to some understandings from all these projects. One of those understandings is that, virtually without exception, the projects that turned out the best were the ones that had the most complete planning. One thing for certain: the projects that won awards were ones that had the most complete planning and stuck to the plan.
I mean. For starters, that's just not how some people work. Some people are planners and need to have detailed outlines. Some people work better when they're flying by the seat of their pants.
I've heard this from people for more than 50 years. I have not found that it translates to better finished products. I've worked with creative people of both types. Early on, when creative types who planned everything would tell me that those who 'fly by the seat of their pants' were just being lazy I would argue that different people work differently. Most of them insisted that good discipline actually helps the creative process. I would politely disagree. As the years went on, however, I've come to believe they were right. On average, the finished product produced by 'disciplined' artists were better than the others.
I was confused by a couple of artists for a while. They were productive, and produced great products, but I didn't see any evidence of detailed plans, only a quick sketch here and there. This went against what I had seen over a number of years. I asked them about it and they both, basically, said the same thing: they did have detailed plans; it's just that those plans were in their heads. They told me not to be misled by the lack of things being written down; they had carefully thought out what they were going to do, they had a plan, and they were executing it.
But even if you're the sort of person who has to have every detail perfectly planned out before launching into the meat of creating, things will change. Things will be edited. Movie scripts get tweaked or edited during filming...or scenes get cut to change things up during editing. I just... ...if you feel like there's a way to avoid that without making yourself totally lose all enthusiasm for what you're doing (at which point why bother) then you've got something figured out that no creative person I know has been able to figure out.
Of course things will change. That's exactly why a detailed plan is needed, so that the unexpected can be accommodated most easily. It might seem counter intuitive, but having a detailed plan makes it easier to figure out what the unexpected means to a project, and that makes it easier to adapt the plan to the new reality. And, rather than dampen enthusiasm, it increases it, because the project doesn't get completely derailed by anomaly. Instead of everyone running around pulling their hair out saying, "what are we gonna do now?", the plan is adapted, people are informed, and things move on.
With things that need to be written/scripted especially. They change while you're writing them. They change again while you're editing. And editing isn't just about tweaking some grammar and phrasing. Sometimes it's about changing huge swaths of the story. Eliminating or adding entire subplots. Changing the ending. Deleting a huge chunk of the beginning. Etc.
Absolutely. That's the process of writing. But you don't publish the book until that process is complete. Some movies (heck, many movies) have gone through huge rewrites, multiple times, before primary shooting commences. Multiple writers, or even writing teams, have worked on the script for a movie, often times over many years. But all that happens before shooting begins. Sure, while a movie is being shot, some things may get tweaked, a character may get emphasized more, or less, but you don't normally see the kind of major rewriting you see during script development. Heck, Harrison Ford is kind of famous for ad-libbing one-liners during shooting. Robin Williams was perhaps the greatest master of the ad-lib. But these are very minor tweaks that don't really affect the script. You just blue pencil them in and move on.
Also, we can be absolutely sure that Ragnar didn't just write the ending without ever having an ending in mind or previously written, because he's tweeted about editing/rewriting parts of the ending before and people got all pissed about it.
I am not absolutely sure about that at all. When Ragnar tweets that he just finished writing the ending, to me that means he has not written it before. He may have the final ending in mind, in general terms (in fact I would be very concerned if he didn't) but I still read that statement to mean it's the first time the exact ending has been put to paper (or electronic document ). That makes me worry that there was never a complete script before development began and, in my experience, that is sub-optimal.