Well count me in that group of people who were disappointed when pleasure island closed down. I get the OP's point, but I think it might also be profitable to attract new customers of all ages by changing Disney's outward view of being "a kids place". I don't think they are hurting for guests, but many people simply have no interest because of the way Disney is geared towards a much younger crowd. That's fine, Disney is a family place, but families consist of more than just parents with young children. I think huge roller coasters would ruin Disney's magic and all that makes it special. But I think they might do well, to advertise those aspects of Disney that appeal to an older crowd.
My idea would be to open a nightclub in DTD that's exclusively for guests staying at a Disney resort who are 21 and over. It might keep some of those "unwanted" out, but entice 20-30 somethings to come to Disney. I'll admit, I'm 27 and while Im not a big nightclub kind of girl, while I'm on vacation Id love to have a place I could go to hang out and grab a drink and/or dance and meet other people my age. That's what Disney is lacking for the 20-30 somethings crowd. It'd be great to drink knowing you have free transportation back to you hotel, as of now if you want to experience some nightlife, you have to rent a car and head over to City Walk.
There are still plenty of teens and 20-30 somethings who love Disney and will spend the money to go as much as possible and who will buy into the DVC and pass the obsession on to future generations, who would also love some more intense rides and nightlife geared towards an older crowd. A family place should have something that meets the needs of ALL members of the family.
I think Disney does a pretty good job of this, but it would be nice to see some nightlife.