The best replacement for mutilate is backstab.

The best alternatives to mutilate are rated as following:
★★★★★  backstab
★★★★  combat
★★★★  sinister strike
★★★  ambush
★★  subtlety
★  shadowstep
★  combat 4.3
★  combat daggers
★  damnation
★  indestructible
★  combat swords
★  hemorrhage
★  protection from black
★  hemo
★  black sun zenith
★  regenerate
★  thragtusk
★  spindle
★  shadowdance
★  shs
  combat dagger
  combat pve
  combat rogue

Your alternative for mutilate is not listed? Suggest!
Speaking about mutilate, one probably shouldn't forget about auto attack macro.

Other search terms related to mutilate and their ratings are:
★★★★★ auto attack macro
★★★ slow offhand
You have in mind a companion for mutilate and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of mutilate in all years. Click on graph for more.
mutilate
backstab
combat