About, oh, five years ago, I posted about my modified DF mook rule.
How does it look after five more years of play?
How does it play?
Well, in the main. The automatic failure on HT rolls has really sped up fodder fights. However, it's run foul of PCs who try to nickel and dime fodder to death - 1-2d spells, play-it-safe body shots, etc. Instead of forcing a maximum amount of rolls (which means fodder go down in windrows), they try to hunt for just enough damage to take them out without resource cost. That plays away from the effects of the rule, minimizing the value.
But when PCs force knockout rolls, fodder just drop and stay down. It's effective and does the job as intended in those cases.
Also, when the PCs specifically take the time to kill the wounded, stop to kill the fallen, etc. I feel a bit lame declaring a moderately wounded orc "fallen" and knocked out. It reduces the interest value of declaring things fodder down a bit for the GM. Not that the PCs can't deal with the fallen as they may, but hey, if I handwave "they're defeated and flee!" or "they fall and some crawl away, the fight's over!" and the players insist on killing to the very last orc, very last rat, very last spider, etc. then we're back to tracking details. When that happens, why not track them all?
Have I changed it?
Yes. Mooks don't auto-fail Stunning rolls, which otherwise makes Explosive Lightning the only spell of choice against fodder. Instead, I use the group roll rules from GURPS Zombies to resolve who is stunned and who is not.
Should I expand it?
I don't think so - it's pretty expansive. It does what I intended.
I've proposed a "High Adventure" or "Swords & Sorcery" level of Mook Rule where fodder gets no resistance roll on resisted spells. I still think that's awesome, for the right kind of game. I may need to run that right kind of game someday. We haven't tried it out.
How often do I apply it?
In retrospect, not enough. I apply it to truly fodder opponents, like orcs and such.
I don't apply it to critters in limited numbers, even when they are fairly weak. Partly that's because if there is only one giant spider, one ooze, a handful of maned rats, etc. I feel like they should do more than drop on the first hit (and the PCs almost always manage to land that first hit.)
I should really a) feature more fodder and b) use these rule very aggressively when I do. There are more fodder fights on the horizon in my game.