Well that actually explains why i was able to finally outdamage our MM hunters on 2phase on Helya, but still, doesn't Vulnerable debuff have to be stacked? It looks like an issue with Sidewinders and not with Marked shot to me, and buffs to single target damage should be enough to compensate for this loss of burst AoE.
I still don't see this as a problem since hunters are not one-trick-pony as enhancement shamans used to be with their ring of fire ability. 28% nerf to damage on one ability is a lot, but it's not like all your DPS got reduced by 28%.
Look at these two logs of a same hunter at 7.1 and 7.1.5 on helya mythic
https://www.warcraftlogs.com/reports...done&source=11
https://www.warcraftlogs.com/reports...one&source=111
It's quite hard to compare his marked shot overall damage because... well, 57 casts vs 44, but difference is not that dire, since with 10 less casts he did only 20% less damage after 28% nerf on damage of this ability.
Look at aimed shot on the other hand - in same amount of casts he did almost twice the damage