The King James Version in its original form is one of the worst translations ever written. It was ordered written by King James of England after the death of William Shakespeare in honor of his beautiful writing style, thus the author that wrote it had motive to match Shakespeare's writing style. The biggest challenge a poet faces is choosing the best words to match the poetic form which most likely forced the author to make alterations from the scholarly translations.
There have been revisions to the original King James Version which are noted with a Authorized by the church.
Finally, New Bibles translations are not based on old ones. The New International Edition for example is based on the oldest known Hebrew, Aramaic, and Greek editions overseen by hundreds of diverse scholars, and many phases of refinement before ever reaching the public.