[Meta thread] Iron's PokeRole Adventure: The Skull Ruins

[Iron]

I'd say it is realistic - the reason you can so easily deal lethal damage to a fainted Pokemon is that it can't defend itself. I'd say even a Pokemon at -3 pain can get its arms up in front of its face, or close its eyes, or turn with the blow a bit, or flex muscles where you strike.

D&D has a similar rule - attacks against a helpless opponent are crits.