I'd just like to see a park do a "New York in the 80's" (1989) theme... bit of Central Park, bit of Coney Island, bit of Manhattan in the period... Ride based around a News studio... town getting struck by a storm everytime a train goes... Relatable theme to thousands of blockbusters. An epic tracklist to go. Done.
I don't mind Country and Western themes being done lots. They are exciting and fun and can always support a good atmosphere. You don't have to work hard to 'get' it. Everybody can recognise the Big Country, Rawhide or Cotton Eye Joe. I would like to see a spiced up version though rather than so generic with a more modern twist.
Any IP's tend to get a bit more attention. You see your favourite film theme in a theme park, your likely to jump for it right? Saw, Harry Potter?
I see theme parks like film sets. They have a genre to fit into. They have sensory conventions that are applyed to get the point across to the audience (guests). I think even all decent unique themes have something relating back to the generic themes because it works well, theatrically. When you have something like Hex or Nemesis (unique, awesome themes) you, to connect it to the guest, have to explain it to really see it right because its totally new to that guest, which takes time, which takes away from the theme a bit if they are looking at it like 'WTF is this, ahh ok I get it now, but the fun has now worn off after a lesson on the dam thing'.
A film theme you know the story. You konw what you are getting into if you have seen it. Same with a loose generic theme. It doesn't need to be explained. Only the scenario based around that story does.