Here’s an excellent presentation by historian John McKee Barr from his book, discussing the major critics of Lincoln. He does a pretty good job of outlining their main points. He also shows why they are wrong.
From the video’s description: “John McKee Barr talked about his book, Loathing Lincoln: An American Tradition from the Civil War to the Present. In his book, Mr. Barr argues that in order to better understand why Abraham Lincoln is so revered that it is also important to understand the criticisms of his detractors, including the charge that he exceeded the powers of the presidency granted by the Constitution.”
You can watch it here.