Just Cause 5 has taken 6 years to make, I'm sorry to say but I don't think it will ever release. From the changing of developers, and also the rushed development and failure of 4 sales-wise makes me think that Square Enix has given up on the franchise all together.
Sorry folks, but I don't think Just Cause 5 will ever be a think. And I hope this comment ages like milk. But I doubt that'll change.