Woundweaver said:
One problem with that is any character who does large amounts of damage may kill non mooks easier than mooks. We had a barbarian who did all power attack all the time. Since the rest of the party was typically boosted his attack roll in some way (bard singing, rogues flanking, mage hasting, etc), he tended to hit fairly often and for large amounts of damage.
Actually, I think the easy way to handle that is to go ahead and let the player roll the damage as normal, and it just does "spillover" damage.
Take the "average" or middle damage of the weapon type, and anything over that counts as an additional "hit".
So a longsword does d8 damage, just say every 1-4 points of damage is a hit.
If the character in question is doing enough damage to the front rank of mooks to take them all out, and still has damage left over, then the front rank of 'em goes flying and slam into the ones behind, and disable them.
Woundweaver said:
Also with spells, does it require three disintigration or fireball spells to kill the mook? Or will 3 level 0 acid splashes do the same thing?
Again, I'd go with the damage spill over idea for something like these spells. The Disintegration bolt passes through these lesser mortals, the fireball spell just toasts 'em, and so forth.
Something like an acid splash is enough to take out a single mook. Said mook start screaming and rolling around clutching his face as acid runs into his eyes and causes the flesh on his face to bubble.
I've been doing the "HD = number of hits" idea for mook types for a while now, and it works great. Mooks serve two purposes: 1) Use up a bit of the party's resources and 2) Make the players feel like their characters are bad-asses.
I don't tend to use 'em much as a way of siphoning off party resources. It feels kinda cheap to me to do it that way. I'd rather give the party something more like a "real" fight if I'm trying to soften them up for the Big Bad.
But to make the players feel like their characters are Bad Ass Mother@#$%... yeah, it works great. You can start off doing this at first level, and it helps to give the game that "larger than life" feel without actually increasing the group's powerlevel at all.
And when they hit the non-mook fights, the group has that instant "ok, these guys are serious" realization when they bad guys don't go down like chumps.
Some narration helps a bit with this too. The mooks and weaker stuff in my game is inclined to scream, gush or fountain blood, explode, and stuff like that. The tough guys might yell, spurt, catch on fire, and so on. The hardcore grunt, have blood flow, have their skin crisp and blacken. Basically the tougher the opponent, the more reserved the description of the effects. This helps to reinforce the mood too.
Mooks are "wah00! Mow 'em down guys!!", whereas the tougher ones require more thought and care.