I suppose it is too much to expect American history to overcome the deification of Lincoln even at this late date. I certainly wouldn't expect Spielberg to be the one to do so, but I'll read reviews of this movie with interest.
My own opinion of Lincoln is that he was a cynical politician consumed with ambition to be President. Consider these facts:
1. Although it was the leading moral issue of the day Lincoln is oublicly silent on the subject of slavery until quite late (1850? from memory.) His behavior was certainly consistent with his famous statement of indifference to slavery compared to preserving the Union. Why historians should have given him a pass on the moral question on this basis is a mystery to me.
2. Lincoln opposed slavery, but did so exclusively on the economic grounds that the slave was robbed of the products of his lifetime of work. Although he had occasion to observe slaves working under harsh conditions during visits to the South those experiences never seem to have aroused actual sympathy in him for the human suffering of blacks.
3. Like other men whose whole lives were devoted to political ambition (Ed Koch, Hitler), Lincoln never had a friend during his adult life. What kind of person has no friends?
4. As a lawyer Lincoln represented a slave owner named Matson who sued in court to recover his property, a fugitive slave woman named Bryant and her children. The court did not agree.
Lest we give too much deference to prevailing opinion of the day, consider the opposite case of John Quincy Adams who dedicated himself to working against slavery after finishing his term as president.
5. When Gen. John C. Fremont issued his own proclamation as military governor of Missouri freeing the slaves in that state, Lincoln promptly re-enslaved them.
6. There should be no confusion about the cause of the Civil War, which was not to end slavery. Indeed, the notion that huge numbers of white men would could be induced to volunteer to fight for the rights of black people at any point in US history is ludicrous on the face of it. The Civil War was fought over whether the industrial North or the agrarian South would control the federal government. Determining whether new states would enter the Union as slave or free was crucial to that question and the reason that the issue did not reach the point of warfare earlier in the 19th century.
Lincoln took pains to avoid the misunderstanding that the War was to be for the benefit of black people by refusing to meet publicly with Frederick Douglass or other abolitionists.
After the long war, however, in the public mind the moral achievement of abolishing slavery was probably the only effect that could justify the massive loss of life. So, American historiography settled on slavery as the cause.
7. Lincoln deliberately provoked the War by refusing to evacuate Fort Sumter, which the military had advised him was indefensible. Lincoln thereby initiated the American tradition of starting wars in a democratic country by getting yourself attacked first, which was the method of choice in the Spanish-American War (battleship Maine), WWI (Lusitania), WWII (Pearl Harbor), and Viet Nam (Tonkin Bay incident.)
8. Lincoln's theory that by joining the Union states forswore the right to secede is without basis in the Constitution or its legislative history. Lincoln based his belief on a mystical idea that the Union somehow preceded both the Constitution and the Declaration. Mystical ideas in politics are usually a cover for economic interests. As a lawyer Lincoln worked for the megacorporations of the day, the railroads, whose economic interests would best be served by an intact and expanding Union. Indeed, the building of the first transcontinental railroad was a Lincoln project.
9. George Templeton Strong, a prominent NY lawyer of the day who met with Lincoln while working on the Sanitation Committee, remarked in his diary that he would have found Lincoln more acceptable if only he didn't tell so many dirty jokes.
10. Lincoln's murder at the end of a successful war, occurring as it did on Good Friday in a Christian country, cemented his memory as a martyr to a great moral cause. A dubious claim, as I have pointed out.