From what I've read this can't impact parks east of the Mississippi, for Spiderman, X-Men, Fantastic 4, and one other thing Universal has contractual rights to.
I don't really want to see these characters in a Disney park, anyways, but the merge should be very profitable for Disney in the long-run.
Movie profits are going to amazing... In the past decade of movies alone Marvel's made around 2-3 billion.
Until the contract ends.
In which one of two things can happen:
1) Disney/Marvel can make Universal pay an arm and a leg to keep the rights and sign a new contract.
2) Disney can acquire all the rights and not let Universal have the option to sign a new contract.