And I'm not saying don't prepare at all, I said I think it's a good idea to look over maps, see what's where, get an idea of what you want to do. But there are others like me that stressed out over exact touring plans, and really, I think that is a waste - because odds are high that something will detail those plans.
I interpreted your original post as intending to be helpful to those who, as you said, make take away from these boards that they can't have a successful visit in the summer without a touring plan. I agree that as you found that advice is not actually one-size-fits-all.
However, I disagree with the implication you make here that if you are not going to follow a touring plan then looking over maps, reading ride descriptions, and getting an idea of what you want to do gives you the same information. One very important thing that the first time (or as good as) visitor gets from the exercise of making a touring plan and no other way is to
know roughly how long it will take to do the stuff that you want to do. Many first-timers do not have a good alignment between what they think they will get done and what they can actually get done in the parks, and fixing that before arrival day can help avoid some major letdown.
I know you write that you threw your plans out after a couple of days, but I'm pretty sure that you didn't forget everything you learned about which rides build lines fast, and that you drew on that knowledge when making decisions about what to do next even after your plans were left at home and you were flying free. It's likely you also didn't forget what you knew about how long various attractions take, and were able to leverage that when making decisions, knowing that choosing to do X meant you would probably not have enough time for Y later. PPs in this same thread have said much the same thing.
Even though many will be perfectly fine without it, I think advice to first time visitors to consider making some touring plans no matter what time of year they are going is sound. Making touring plans is, IMO, the immersion method of learning WDW "language". Continuing the analogy, what is unfortunate is that you were inaccurately made to feel that you wouldn't be able to get around or make yourself understood by natives unless you had learned enough that your verb tenses, conjugations, pronouns, comparatives, and possessives were perfect, and this caused you a lot of unnecessary stress. I can't speak for you, of course, but I think the waste was not the time you spent making touring plans, but that you "
stressed out over
exact touring plans" because the advice you were given wasn't placed in the proper context.