Being changed isn't the same as being nerfed.
If it's a change which make something worst/less powerfull, it's a nerf.
Both nerf and buff are inherently a
change, neither mean that it has to become OP or useless from that change, it only describe either an increase or decrease of it's effectiveness/power.
In my book, when your flanking go from "deleting" the opponent to seeing him "
respond to that fire and take action ", even if the result should still be the death of your opponent you are still less effective, it's
nerfed ( and that's Dice only using only a 1v1 scenario, the impact of the change only get worst as the number of ennemy increase ).
It's like saying that an overall decrease in damage of most weapon at different range depending of their niche, isn't resulting in an higher
average TTK. It simply make no sense, at best you could say so if you also decrease that TTK at other range with an increase in damage, then yes
maybe it could end up with the same average TTK. Otherwise you are increasing the average TTK because people won't miraculously only encounter their opponent at that perfect range.