My biggest problem with DHS isn't the lack of new attractions- its the lack of cohesion. The park doesn't know what it is anymore. It is missing all the edutainment that Disney does better than everyone else. Ever since it stopped being an actual studio and the animation dept was shipped out of town, it has lost its identity. Part of what made DHS (then MGM) so great was that it had thrills combined with fascinating behind the scenes type stuff.
It really is a random assortment of stuff anymore... AI, Muppets, Pixar, Star Wars, Playhouse Disney...
I just think it really needs to figure out what it wants to be first then we can worry about it getting new attractions.