You are right on both counts. Colonel Opdycke's refusal to obey General Wagner's direct order would have cost him dearly (if Colonel Opdycke's brigade did not save the day, at the end). Some sources say that General Wagner was either drunk, or "tight", on the day of the frontal assault by General Hood. General Wagner resigned soon after the Battle of Franklin.

Also, you are correct that in Opdycke's letters, he was chiefly clubbing not the enemy in hand-to-hand combat, but the fleeing union soldiers (shikers) while on horseback. In any case, this was probably the right thing to do, under the circumstances.

I would hate to think what would have happened if the Union lost the Battle of Franklin, and the Battle of Nashville that followed!