It's a question of Maketing.  In the 80's Animated films were pictures 
you could drop your kids off at while you did something yourself.  By expanding 
the shows to include Adult themes without sacraficing the Kid appeal, Disney can 
increase attendance because the Parent's will want to see it with their kids, 
rather than using it as a suregat babysiter.  Also folks who loved Animation in 
their youth will feel a lot less guilt at seeing it because it's clearly for 
them as well.
	Oh, and I assume you've got a very positive attitude about the news that 
Disney will be distributing Miyazaki's films?