Then why has rez ALWAYS been Mercy’s only playmaking ability?
For crying out loud, one of the most common forum topics pre-rework were pleas and suggestions for Mercy to get a mid-fight E ability. These topics were open (even eager) to nerf mass rez in exchange for an E.
Give Mercy another way to have burst impact (that isn’t Battle Mercy), and players won’t be forced to rely so heavily on rez.