The idea is to just completely get rid of damage boost, and replace her alternate fire with the pistol. No weapon swapping, and no screwing up break points for other characters. Maybe she could even shoot while healing simultaneously. Obviously they would have to tweak her animations and stat numbers.
I never understand people who think that Mercy needs some sort of rework or buff. Mercy is incredibly strong at what she does. If you don’t like her gameplay style due to being too “passive” then don’t play her.