Also, now that Bohannon's quest is over (he most likely has already killed everyone responsible for his wife's death, Johnson was just BSing about the Sgt) his character lacks any real motivation or goals. He's only there because Durant has basically enslaved him.
This particular thing puzzles me the most. In season 1, I got the impression that there was more to these particular murders than simple late wartime blue-on-gray pillaging. I can't remember precise dialog, but there seemed to be an implied ritualistic, almost supernatural motive, behind these murders. IIRC, one of the lower-ranked Federals involved mentioned a demon or devil. Or maybe it was Ted Levine's character (the ringleader). Although, perhaps it was nothing more than simple Victorian-era language usage. Can't be sure.
There always felt (to me at least) that there was something deeper going on surrounding the events of his family's death, the pursuit of which, through clues would lead Bohannon to a deeper conspiracy. Sadly, what has come since then has seemed quite mundane by comparison.