We may see something eventually. But it has also been pointed out that U.S. laws give wealthy individuals fewer reasons to form companies in Panama. It is possible to form entities with secret owners under U.S. law, with a little effort. So the primary reason for Americans to go offshore may be tax-related, for which Panama would not normally be the jurisdiction of choice.
See: http://fusion.net/story/287671/americans-panama-papers-trove...