I'm torn as to whether or not to include substantial design notes for my WoAdWriMo entry in this blog. On the one hand, it might make for interesting reading. On the other, I'm worried about revealing too much about the adventure itself.
In any case, I'll definitely talk about some of my general rules. For instance, there are some things that I think either aren't particularly fun or bog down play unnecessarily when used against PCs: ability drain, devastating ability damage without access to Lesser Restoration or the like, and paralysis. Permanent weakening of characters is rarely fun for their players - and it messes up CR calculations. Temporary weakening of characters can be OK - the Paladin who has taken Intelligence damage can be fun to play for a bit. No one likes to play with Constitution damage, though. In games I've played in, we tend to sleep that off whenever possible... which can slow down the pacing if you aren't careful. Paralysis? Well... I generally don't like effects that take you out of the game. It is fine for PCs to be frustrated, but that tends to make for frustrated players - which isn't a desirable thing. So, unless there is some sort of weirdness that makes them palatable, effects like these just won't show up in games I design or run.
I'll note here that this makes undead tricky. I may have to write up some new undead creatures in order to fill the gap I just created for myself.