I got about 8 pages into this thread, so perhaps this has been covered prior to this. Point of personal experience, I've fenced, and studied HEMA for about seven years now. What this means is, every Saturday I go out to the park with some other guys, and do my best to hit my friends with steel swords. I bring this up to allege that I have some experience with damage on a "miss"
Some of the guys I train with are so aggressive that even when you parry their blade, either with your blade or block with your buckler, it hurts. They're strong, they're aggressive, and the force of their impact shocks your arm, loosens your grip, and wears you out even when they technically "miss". Oftentimes, if you counted up points, I won, as in, I managed to strike them in a more deadly fashion than they struck me, if they struck me at all(and sometimes I lose...we're all about equal in skill level). But against these guys, by the end of a bout, I'm bruised, sore, and worn out to a much greater extent than I am after a bout with someone else who might have other talents but is less aggressive. So the Reaper thing makes complete sense to me. Even when these guys miss they hurt.
If nicking an enemy to death with misses is a real problem (I'm not convinced that it is), perhaps a rule that an opponent can only be killed on an actual hit. So you can wear a guy all the way down to 1 hp with "misses", but the last strike must come from a successful hit roll. That would seem to bridge the game between reapers strike being a useful ability and "realism".