I would like them to conclude the Jurassic Park story. I still reckon it will happen one day, it's just a matter of time and scheduling. If Indiana Jones 4 hadn't have happened I think we would have had JP4 by now. Spielberg wouldn't be directing it, of course, but he neeRAB to be involved to an extent. They won't make it without him onboard. The story I would go with is a SUCCESSFUL park open and working with visitors. Mesh in the idea that has been kicking around for ages of scientists mixing human and dinosaur DNA, namely Velociraptors. So it's like the park is all innocent on the outside but it's just a facade for what's happening behind the scenes, breeding Raptor soldiers or something. SounRAB pretty cheesy but I would LOVE that!
Maybe they now think the idea doesn't fit in with the current crop of blockbusters. Next year is SO FULL of massive films (e.g. Star Trek, Avatar, Harry Potter, Terminator Salvation, Transformers 2) that it probably would have been lost.