Jefferson Davis thought himself a military leader—his replacing of Joe Johnson with John Bell Hood as head of the Army of the Tennessee at Atlanta was a Blunder of the first water. He gave Georgia to Sherman and his Bummers. After terrible attacks at Franklin and Nashville the Army of the Tennessee was no more! The Union Army should have given a medal to Hood and Jefferson Davis for their foolishness. Many in the south wanted Lee to take over and rule as dictator! Not really a bad idea.
Thomas, OTOH, was a master strategist, a brilliant logistics expert, a better trainer than McClellan, and it can be honestly said that he achieved tremendous results with relatively few casualties.
Had Grant, and his favorite Sherman, not hated jealously him because of his economical successes on the battlefield, he would be much more famous than he is today. They worked tirelessly to in DC to undermine him and even put Schofield, their spy, on his staff! BTW, Grant, Sherman, and Schofield ran the country and the army for many years after the war. Schofield, like John Kerry, awarded himself many decorations and was taken to task for the lies in his memoirs ... many of themn against Thomas!
His undeniable masterpiece: The Battle of Nashville in which he broke Hood's forces and secured the Western Front. He beat Hood with an Army he built, after Sherman took all his best divisions, artillery, and cavalry mounts in his dash to Atlanta, which actually accomplished little. In fact, in stripping Thomas of men and supplies, he damn near cost the Union the battle form the west.
Hood was an excellent leader, but his mind became addled with addictive opiates after his horrible injuries and amputations. He literally had to be strapped to his horse!
It was suggested that Bragg so hated Davis that he may have done what he did on purpose. Of course, Bragg argued even with himself-that was the way he was.
If the idiots Lincoln and Halleck would have let Grant do what he wanted at the beginning, that war would have been over very early. Grant feared no southern general like he feared Johnson. He knew that if the south would have followed Johnsons tactics and draw the war out, the north would have grown so weary of the war that they would have sued for peace.