I think it really depends on how you plan to use it. If I wanted for example to go to the parks for four 3-day trips with hopping over the course of the year and my trips were spaced at least 2-3 months apart, I don't really think I would have trouble booking what I want, and even buying the dream key I would save money over buying parkhopper tickets.
I live in northern California and have had a
Disneyland annual pass mostly continuously (let it expire a couple times when there was longer than usual between planned visits) since 2006. Both my sons currently live in southern California, so I knew we would be down that way to see them if nothing else several times over the next year. I ran the numbers and decided to take the chance on the dream passes for my husband and me. And, yeah, the holiday calendar situation stinks for someone like me who wants to plan out a lot of days in October and November with even a possible quick return trip in December. In my case, I decided to pick my priorities and be ready to be flexible, to compromise, and to have alternate plans. We did 3 full days this month plus several hours on arrival day and a couple hours on departure day (scored that reservation the night before when relaxing and enjoying an evening snack in the park). So we managed to enter the park 5 days during our first month of pass ownership. Was I able to book all the days in November that I wanted...no. I had booked the two that were most important to me before leaving for the October trip, but by the time we checked in on the first day of that trip all the remaining desired days were gone but one. But October was all about Disney for me and November we will be down in part for Disney but for other reasons as well. I was able to get 3 of the days I wanted but would prefer to have 1 or 2 more, so I will stalk the calendar. In the meantime, unable to get my November dates, I grabbed December 30 and 31. Will I go? I'm not sure yet, but since I paid for that dream key and I would like to go, I decided I would book a hotel room and grab what I might want when it was available and not have regrets later. If I don't go, some last minute planner who owns a dream key will be very happy.
So really the biggest problem that I see with all of this as a non-local key holder is that it involves a lot more planning and uncertainty than the old way of just having an annual pass and going. So I wouldn't rule out the magic key for non-locals; I would just say that you have to think ahead and decide what the minimum you need to get out of it is to feel that it is worth the effort to get the value from it. And that takes more planning and more math and more flexibility. It's a trade-off as so many things are.