I hate to disagree, but historiclly this is exactly what happens both at the level of the individual, and also at the strategic level. At least part of the effect is caused by avoiding the bulk of the enemy forces (which are out of range or pointing the wrong way). Consider ther following:-
Sergeant A. York and a few others managed to enfilade several machine guns that were pinning down the US advance against German forces. 17 soldiers took part in the assault, whittled down to 8 by enemy fire, however sergeant York continued on alone, and single handed managed to kill sufficient enemy for the others to surrender to him, allowing the advance to resume.
On a macro level, the
charge of the light brigade was effectively into the right flank of the advancing Russian army. It was unintentional, resulted in the Light brigade becoming 'broken' in our terms, but stopped the advancing Russians and effectively 'won' the battle (or more accurately it caused the Russians to break off their attack while they dealt with the threat).
It is worth noting that experienced players do attempt to get the additional assault resolution pips for BMs and formation numbers etc to tilt the assault in their favour, so using the Marines Vs Orcs example, the ideal clipping assult might be to have another formation fire on the Orcs, and then have four Devastators lead by a Chaplain in FF with three orcs from a 'uge warband. Despite being heavily outnumbered, with luck the devastators kill the three orks for no loss, and with the Chaplain will be 4+ on the resolution, killing off further orcs as hackdowns. This reflects the devastator's superior firepower wiping out successive waves of Orks as they try to get to grips with the marines, and ultimately the remainder running away - seems reasonable to me.