I've seen the Stephens book but not the Davis one. In what way were these books revisionist?
This is nothing unusual. Hindsight is 20-20 they say. You always try to put your best foot forward, especially if you were on the losing side.
Let me give you a case in point. Davis wrote afterward that the CSA had no aims at expansion or ambitions beyond their borders. Yet, documentation shows that they clearly had their eyes on New Mexico and Arizona Territory, the Indian lands later known as Oklahoma, as well as Kansas, Nebraska, and other plains states. After all, the CSA did accept representative from Missouri and Kentucky - states that did not formally secede.
"The most comprehensive articulation of the view that Southern secession was a legitimate constitutional act is found in A Constitutional View of the Late War Between the States, written by Alexander Stephens, vice president of the Confederacy, published shortly after the war. A Constitutional View purports to be a comprehensive treatment of American constitutional history. But its comprehensiveness is illusory. It soon dissolves into a hash of selective evidence and sleight of hand whereby the natural right to revolution embodied in the Declaration of Independence is transformed into a constitutional right to destroy the Constitution. A Constitutional View is, alas, another refrain in a song composed and performed by John C. Calhoun and the South Carolina nullifiers."