this one says Johnny is not officially on board yet,but I guess Disney wouldn't have started the project w/o some sort of approval from him:
" Depp was “close” to signing on for the film back in 2011, but has yet to officially do so. It’s also unclear whether previous co-stars like Geoffrey Rush and Keira Knightley will return. What is clear is that the multi-billion-dollar franchise is sailing forward."
"Making a number of major additions to its release calendar, Disney said Monday it will open Pirates of the Caribbean 5 on July 10, 2015. Johnny Depp will return for the next installment, although no director is yet attached"
well then Johnny definitely doesn't care what the script is as they've just hired a writer.