They have tried this and it doesn't work. Alien Encounter frightened children and separated them (strapped down) from their parents - - a cruel dystopian future if ever there was one.
Also Tomorrowland '98 in its rusty, catpoo colors, with rotting, abandoned rides and dreary agrifuture plantings was a reflection of global corporate madness gone awry, as dystopian a future (or present reality) as one could get - - and it too was rejected by the public.
Disneyland thematically is about Walt Disney himself -- the man was a utopian optimistic futurist and that's what we need in Anaheim. We need hope, not trendy gloom. Reassurance, not social relevance.
"There's a Great Big Beautiful Tomorrow shining at the end of every day."
"Tomorrow is just a dream away."