Terry Rossio is one of the original script writers and is probably given credit since he and Ted Elliot wrote the first draft.
Response from the man himself!
Re: Pirates 5 sets sail 2015 - without Terry?
Posted by Terry on Tuesday, 15 January 2013, at 9:00 p.m., in response to Pirates 5 sets sail 2015 - without Terry?, posted by Sir Quackly on Monday, 14 January 2013, at 1:23 p.m.
>> Variety didn't specify if Nathanson will co-write the script with Terry or if
>> he rewrites Terry's script or if Terry is completely out.
You would think there would be clear and concise answers to these kind of questions. But that's not how the film business works. Gotta love Hollywood.
The problem lies largely with entertainment reporting combined with people's expectations. For example, right now, I wouldn't venture to guess whether there will be a sequel, when it might be released, or who will be involved, and here's the clue: you have to wait until there is a director involved.
Of course fans get frustrated. But I often cite Indiana Jones 4, which took quite a long time, with many announcements along the way. But until there is a director on board in a real pay or play situation, everything is speculation.