Therumancer said:
Don't worry about careful. That part is in the bag. For a game like this to work, more preparation is required. Between reading sourcebooks, drawing up antagonists a bit more full-bodied than "Vampire Foozle," and so forth, I expect to spend 100+ hours just getting the campaign ready. We're going to stay in one community the whole time, so I intend to have a robust stable of NPCs with conflicting interests, dirty secrets, and quests to hand out.
Actually only Darkon rewrites memories. The biggest problem in other domains is probably Madness saves. And those are only a problem if you see them as such. A dose of nyctophobia can be great for roleplaying. That's actually the goal. Don't hurt the PCs to be mean. PCs always get hurt; ask any party healer. Find subtle ways to hurt them, let them know that consequences can be a bit more complex than hit point damage. Evil can arise from sin and vice, but also from virtue taken too far, or acting in ignorance. Good has its price, just as evil does. It's simply a more realistic take on D&D than the normal avalanche-of-goblins, I'm-wearing-my-PC-badge-so-everything-I-do-is-okay approach.
Different domains stay different the same way they do on Earth, through geographical separation. In a world without cars (lacking even horses in some cases) a trip of a few hundred miles becomes a perilous weeks-long undertaking. Only those with real reason to travel will do so. Isolation keeps cultures unique. Sure, borders can be closed, but it's not really necessary. A single string of mountains with bad roads suffices.
Plots are only straightforward if the GM makes them that way. For example, I'm using the "kill the rampaging werewolf" plot. Normally this would involve tracking the beast, staying up nights, watching for odd behavior among the townsfolk and visitors, and being patient until the creature reveals itself, at which point it is brought to bay and killed. Simple, right? Except this werewolf also seems to control local wolves, and appear and disappear at will. The town's best tracker is stymied. Careful analysis can reveal that the beast's attacks aren't random or confined to the town as might be expected. Rather they seem to target the logging operation at the old forest. Early attacks took the form of sabotage and terrorizing, only killing later. If the PCs corner the beast, it will turn into a bird and fly away. So now it's a druid or wizard or something attacking people because it wants to rather than because of territorial urges. It's time to put away the silvered weapons and consider other tactics. If PCs show reason, the druid explains there's a buried evil in the forest, magically bound so only the will of man can dig it up. Unfortunately the greed of the logging boss is close enough to what's required, and the evil sleeps only fitfully these days. If he gets too close, the evil will awaken. So what will the PCs try? Get the greedy boss to walk away from money, incidentally robbing the town of its timber supply? Ignore the druid and risk awakening the evil? Go into the forest themselves to try and slay or secure the evil? This is further complicated by the loggers' anger towards the druid, the bounty hunters tromping through the forest trying to slay an evil lycanthrope that doesn't exist, and so forth. It has also attracted the secret interest of the local hag covey, who know the evil is actually a buried zombie dire bear and want to make a pet of it.
I've explained this is a low-level campaign. Fear loses meaning when PCs can march into the lair of the local vampire lord and ash him without breaking a sweat. Even throwaway creatures like zombies are often empowered beyond their normal stats. Care must be taken at all times. My players are fine with that.