I admit, I noticed that Kill Shot wasn’t available when the mobs were close to me but I didn’t notice an increase in Volley’s damage – probably because I don’t get to use it too often while soloing.
So apparently Kill Shot being able to fire at point blank range was a bug that was fixed. Alright, it makes sense since it does rely on a ranged weapon.
The other tweak was increase in AP value for Volley… I think. I admit, I skimmed these notes: http://www.wow.com/2009/09/25/patch-3-2-2-sees-stealthed-hunter-nerfs/
Thanks to UFTimmy for the link.