For whatever it's worth, this is how easywdw operates:
http://disboards.com/threads/who-has-the-best-crowd-calendar.2965605/page-3#post-45681529. There isn't necessarily a lot of emphasis on the past, though it's certainly taken into account. I don't do anything unless there's verifiable, concrete information. That's why you won't find any information on crowds further than about 6.5 months out. There's no projections that far out and if I were to tell you about August 2016 or something ten months in advance, I'd just be guessing based on how August 2014 and 2015 were. As others have stated, guessing isn't going to take us very far. It's also why you won't find any recommendations around Christmas. Disney's projections for about two weeks there are the exact same (high) numbers every day. Again, I could guess or base it on last year, but I don't think that would ultimately be helpful.
One problem that is occasionally run into is that the parks are legitimately busier than expected and you do see a lot of problems with staffing when that happens, which in turn compounds "crowdedness." Since we're talking about Animal Kingdom on November 14th, that did legitimately happen as the park hours were extended by an hour on the day of. Attendance wise, the parks are not significantly busier this year than last year or the year before. The increases are in the very low single digits, particularly at the parks not named Magic Kingdom. My guess is we'll see increased staffing and longer operating hours next year, which should help combat the feelings of "crowdedness." I could go on for a few days about data mining, reduced staffing the effects of MyMagic+, etc. I've seen a lot of people asserting that MyMagic+ is offering some kind of portal into guest behavior, but that's either not happening or
whoever runs Touring Plans is in charge of interpreting it, because we really aren't seeing an increase in the accuracy of the projections. They're actually trending in the opposite direction. Hopefully that instills confidence.