They were doing this at Gardaland last year, and it was annoying. I was there in August so it was heaving, and Kung Fu Panda, Sequoia Adventure and Shaman (ie Magic Mountain) didn't open till 12. Shaman was the "new" attraction and had an awful throughput (1 train only, with VR) so a lot of people will have missed out on it completely.
I'm really surprised they chose Forbidden Valley because that will really affect the hotel guests who enter the park there. I wonder how much cash it actually saves!