Idk if this counts as proof of how it was in classic but:
http://www.magecompendium.com/pet-behavior-library.html
The primary determinant of the Hate Value of an attack is the potential damage that attack could have normally done. Thus Hate ignores both resists and criticals. All attacks with the same weapon or spell generate the same amount of Hate regardless of how much damage they actually dealt, even if they miss or are fully resisted. Spells that do not do damage have a Hate value assigned to them. Some, like Tash and Slow spells, have a high Hate values. Others, like Cancel Magic or Malosini, have a low Hate value. Healing and buffing an NPC's enemies also generates Hate.