But that's not a concrete number. Ok let's look at 15K, that number would be, I'm assuming the number at 100% maximum occupancy over a week. rarely does deluxe reach 100% max. or at least according to disney they are averaging 85% occupancy at the deluxes. Next your also making the assumption that 100% of the deluxe/dvc guest will buy into any new premium pass. Once again the probability of this happening is really, really slim. I think the probabililty of 75% buying in is pretty optimistic. Here is where you're absolutely right, the devil will be in the details. For example
Disney dining plan, although it's offered to everyone, this years prices are so outrageous that it's priced its self out for many. Would I pay for this pass at 80 a head extra? Maybe. would I pay for this pass at 150/head? NO way.
So now you've taken your 15K number and decreased it down to almost 9K. Now throw in the fact that this new number is now spread over various days, various times, and various parks and the probability of this causing a significant problem has decreased even more.
Now the problem with the candlelight dinner analogy is that the event is held in a very limited window of time "forcing" the guest to stake their claim earlier because you don't have the option of waiting 3 hours. Think of it as a 5 lane highway suddenly dropping down to 2 lanes, at the merger point you've got a traffic jam. That's what happen with Fantasmic, when the reduced the showings to 1 specific showing, you had massive problems because now the folks who had 7 days often 2 times a day to see the show were funneled to 1 time. Now with a premium fastpass in reality you wouldn't have that bottle neck. Whats the probability that 700 PFP owners will show up at TSM with in the same hour? pretty small.