Correct me if I'm wrong, but wasn't the Omnimover going to go where Trikes was? If they put the coaster there a dark ride can't happen.
Regarding box office numbers, JW's numbers will probably impact the expansion. 2015 is crowded with movies, and while Jurassic World doesn't have much to face opening weekend, the following weekend is where it'll get crushed. The Fantastic Four reboot (which will probably be delayed or go back to Disney) and Pixar's Inside Out come out then, but even if the former gets delayed it'll still have to face Inside Out. Just look what happened to Man of Steel with Monsters University and World War Z.