Something I still wonder, and I truly wish I could have been a fly on the wall for the executives that decided "hey I know, let's open a brand new park with zero previews"...
I mean, so much could have been avoided if they did a month of public previews, limited capacity, hard-ticketed previews, say at $45 a pop. Go in knowing it's not finished, things may not work... etc. It really could have helped out the ops teams, the TM's, and management in how to run this park effectively and efficiently.
Pandora did so many previews, and that's just a land... and in all honesty, the opening day was a complete success for Pandora.