I do agree that the current parks should all be refurbished and added to the max before a 5th park should be opened. That said, I think the rumored "Dark Kingdom" idea is a fantastic choice for the theme of a new park. Imagine, Maleficent's castle as the icon of the park and different themed lands that have to do with Disney villains or just darker toned Disney material. I think it'd be great to explore "Halloweentown" from "Nightmare Before Christmas", the potential for attractions in a land like that could be very exciting. In addition, maybe a dark ride based around Sid's Room from "Toy Story" and the stranger toys that reside there. Perhaps, even an area where an attraction based around Chernabog from "Fantasia" could happen. A park like this could allow Disney an edge to explore some of there darker properties as well as implementing some more thrill rides for more mature guests.