The field performance of L-G 'Bishop' Polk as a Corps commander was probably sub-standard. Polk's military performance was described as being incompetent and willfully disobedient and this consistently hamstrung Confederate operations ('Sherman: Lessons in Leadership' by Steven E. Woodworth, at page 117).
Despite any shortcomings in combat leadership, he helped organize the Army of Tennessee in 1862. His redeeming quality might have been that he was very popular with, and could lift the morale of, his soldiers. As Albert Castel says (writing in the present tense) about Polk in 'Decision in the West' at page 46:
…"his unflinching courage in battle, his imposing presence, and his fatherly solicitude make him popular with the rank and file"…
This view of Polk's popularity is corroborated by Sam Watkins (1st Tennessee), who served through the war, in his own memoir of wartime experiences, 'Co. Aytch'. Watkins, reflecting upon Polk's death at Pine Mountain in 1864, wrote (page 127) about Polk in the following way:
…"His soldiers always loved and honored him. They called him 'Bishop Polk'. 'Bishop Polk' was ever a favorite with the army, and when any position was to be held, and it was known that 'Bishop Polk' was there, we knew and felt that 'all was well'.
Perhaps the depth of feeling and devotion felt by Southern soldiers for Polk can be demonstrated in their message expressed in a sign that they left on Pine Mountain for the advancing Federals to mark the spot where their leader was killed. On page 172 of his published Personal Memoirs, Union M-G David Stanley wrote about the sign found when Federal soldiers ascended the hill two days after the Confederate withdrawal. They found a stake in the ground with a paper sign on its top, which read:
…"Right here is where you Damned Yankee Sons of *****es killed Bishop General Polk"…
The death of Polk likely had a profound adverse effect on the morale of the soldiers under his command.
Woodworth (Ibid., page 117, Woodworth) thought that Polk's death disadvantaged the Union, because his incompetence made him more valuable alive than dead. Woodworth also conjectured that if Polk had lived, Davis would have probably replaced Johnston with him in the next few weeks, and this perhaps could have shortened the war by months.