Once again, there is chatter about how Turn Undead should work. The latest edition of your favorite fantasy gaming is vexed over what to do.
Zombies turning and fleeing? Seems impossible actually. Skeletons so scared that they turn around and face the wall? That’s fun and heroic. Mummies flailing their arms like they are doing the “monster mash”? That’s exactly the kind of fantasy I wanted to be playing.
[Assuming pandering tone.]
So. Why doesn’t turn undead just do damage and increase you AC in regards to undead?
Why is this so complicated?
I think I’ve written this in 3 different d20 books.
The truncated version is this:
Your Cleric Level in d6 dice against undead X times per day in a 15 foot radius. Paladins roll d4s. You can choose a Feat to increase the damage and another to increase the range. This ramps up fast, so you may need to temper the values to match the edition you are playing.
You Level is also added to your AC (for the purposes of undead) for 3 rounds. You can select a feat to increase the duration.
Can someone get a towel for my brow. I’m sweating here?
post world games 
Turn undead always felt like someone took something cinematic and tried to make it fit the D&D mechanics. I totally agree with your mechanical assessment of turn undead, but there is a small part of me living in the cinematic idea of it. I picture someone channelling the divine, saturating an area with antithesis of what the undead are. Something so pure, so powerful, that even things that can’t know fear, succumb to it. A moment of pure righteous glory where the gods themselves say “THIS PLACE IS FOR THE LIVING”, and the undead must obey. It’s the unfortunate moments after that, that sour the vision. The undead are leaving, but that means you won’t get your treasure or xps. You can’t let them shamble away into the nether; you MUST destroy them or else you won’t level up, get a +1 sword, and show the villagers you mean business. If you don’t kill them, they’ll just come back, righ? I hate to break it to the villagers, the undead always come back. Adventurers don’t clean up zombie corpses and bone piles when they’re done. The fledgling necromancer (probably the miller’s son.. it’s always the miller’s son) will find the bones, get a few spells right and we’re back to square one. At least now the party has a +1 sword to deal with things.
I think there are other options mechanically that can make turn undead a valuable asset, and at the same time make it more fair for the undead in our campaigns. What other maligned group of monsters have so many tools designed for their destruction? Sure, dwarves hate giants and rangers can really smack it to some orcs or goblins, or whomever they’ve chosen to hate, but undead? They really get the short end of the stick here.
Undead energy animating bones doesn’t seem like it should dissipate because you’ve dealt a prerequisite amount of damage. Perhaps turn undead is what allows the undead to be killed. Smash a skeleton, and in a few days it will reform. Smash it, then turn undead, and you’ve released the energy. Village saved. Everyone is happy and it was a fair fight.
just my 2 cents.