OhaiDur, thank man for the suggestion.
There will be big update on DK for 5.4 (which i'm working on) with many new feature (anti-magic shell before a sheep hit you for example) AND the hotkey feature.
Currently HB API only support CurrentTarget and FocusedUnit there's no Party1/2/3 or Arena1/2/3 so all I can add is hotkey cast on Me/Me.CurrentTarget/Me.FocusUnit... that good enough for Arena.
My coming Shaman auto Hex focus all the time, it quite good at 2k rating so I think similar feature on DK 5.4 update will serve you well.
Hey Tuanha, how about adding pet leap to friendly target if scatter shot is present?