I assume this will work similiar to the abilities of generals in Kingdoms.

While not one time use, I think the abilities will be things like, better aiming, better in a area, (infantry, Calvary, artillery), or maybe better discipline.

The general will probably not be one shot kill, but I doubt he's going to be able to solo entire units either, if he gets in the thick of it, he's toast with probably a few shots or one cannon shot. Unlike the barrage of arrows you could let hit your general's unit in MTW and RTW again and again