Seems like there are myths spreading about incapacitation increasing drop rates? Sounds like a bully beating up a kid for his lunch money to me. Unfortunately, this is in fact only a myth.

Below are the true effects of incapacitation:
  • Enfeebles the enemy
  • Prevents the enemy from using special abilities
  • Alters the materials that are obtainable after defeat (depends on the incapacitation)