4. John Milton
One of the all time great poets and writers, an adaption of Milton's life would focus on three things. The first would be his controversial writings during the English Civil War when he proclaimed that a Republic was the ideal form of government not a monarchy. After the establishment of the English Commonwealth under Oliver Cromwell, Milton wrote several controversial works including one that defended the beheading of Charles I. Due to his writings he was briefly imprisoned by Charles II after the monarchy returned to power. The second key point to focus on was his Aeropagitica, a tract against censorship that is one of the most famous of its kind. And the third key point would be the writing of his magnum opus Paradise Lost, which has since become one of the most famous works of English Literature. A film adaption would be wise to focus mainly on his life during the English Civil War and ending with the writing of Paradise Lost, which took him several years to complete. There are very few well done movies about famous writers and Milton doubles as having had a fascinating life to draw from in addition to a fascinating body of work.
Casting Choice: Alan Rickman seems like a solid choice for Milton. Who wouldn't want to hear Rickman narrate some of Milton's writing.