That can't be it, because the feat comes from a theme, and themes are not tied to class. If they were trying to pump up the fighter's damage, presumably they'd do something with the fighter class rather than a theme that any class can take.II understand what the designers see in it: a simple, mathematical mechanic to make the Fighter deal commensurate damage (commensurate with the idea of a Fighter being a bad ass)
If you don't want a narrative "miss" to kill an enemy, then don't describe the result of the Reaper feat as a miss! Rolling low on an attack does not require you to narrate the attack as a whiff.What I reject is the idea that a miss (not a "miss," not rolling low on the d20, but actually physically swiping your axe over the enemy's head) should result in a dead enemy on a regular basis. But the way Reaping Strike is described in the text, when you use it against a kobold or a rat or anything with only a couple hit points, this is exactly what happens. You miss the enemy--in the narrative sense, not the mechanical one--and it falls over dead.