So you blame Disney because you can't figure out how to successfully plan while still remaining flexible?
This is how Disney operates, it is nothing new. The same will happen for the Star Wars Land, the same happened for Fantasyland, 7DMT, Soarin, Test Track, Toy Story, Anna & Elsa Meet & Greet, etc etc etc. You can plan to a certain extent, but when you plan too rigid that you do not allow for flexibility, you are putting yourself at a disadvantage, not Disney.
For example, we are going over Memorial Day weekend and Frozen Ever After ever is SUPPOSED to open the day after we leave. Anyone going over Memorial Day that isn't planning for the possibility of Frozen ever After being opened on a limited basis, trial runs, etc is selling themselves short. Plan, but leave room for the unexpected. Unless you control the variables, you have to plan for variability.