This does look like a nerf but Boubouille had said that a lot of stuff has been previously buffed to boost some classes on live servers.
Blizzard Entertainment wrote:
Marksmanshiphttp://www.mmo-champion.com/content/205 ... uild-13241
* Kill Shot now deals 116% weapon damage, down from 150%.
* Multi-Shot now deals 40% weapon damage, down from 55%.
* Aimed Shot! now deals 65% weapon damage, down from 100%.
* Steady Shot now deals 62% weapon damage, down from 100%.
* Arcane Shot now deals 61% weapon damage, down from 100%.
* Chimera Shot now scales from 48.8% of Ranged Attack Power, up from 28.8%.
* Black Arrow base damage increased by 20%, from 3077 to 3685.
* Explosive Shot now scales from 42% of Ranged Attack Power, up from 22%. Base damage increased by 25%, from 558 to 697.