Ruggan wrote:rotting bridges that collapse when carts or more than one person cross at a time,
Would be cool.
animals that seek you down and attack when you're carrying food,
We've discussed things like that plenty of times.
boats that capsize,
Duuuh.
friendly fire for archers
Well... what else would really make sense, you argue?
heat exhaustion from being outside at all during the day,
High summer, maybe. Remember, Northern Europe.
snowstorms that obscure the entire field of vision and prevent one from logging off
Snowblindness I've thought of several times, and that particular effect for becoming "lost in the snowstorm" I've actually considered in detail.

randomly poisonous mushrooms / chantrelles
Most
certainly not randomly.
Wound infections that give permanent crippling illnesses that force you to move at a crawl for the remainder of your character's lifetime
Seems harsh, but if there was a fun cure, or a cool quest line...
critical failures with tools that cause massive HHP hemmoraging
If the effects were comical, rare, and good gameplay, sure. Seems overly on the random side. How could it be prevented?
deadly spiders that hide in stored footwear,
I also want to do rats that eat food out of containers, and leave footprints behind, and a hidden underworld where you'd have to go to slay the rat king of the house. When loftar does the new inventories, I'm hoping a lot more stuff like this (inventory interactions) will be possible.
birds that have the potential to poop on your character and bring his/her happiness to -100%
Good idea, although happiness will be removed, at least as it exists now. And not by 100% of anything. More subtle.
dental diseases that prevent characters from eating chewy food
Food effects are so much fun. Worms and other parasites from drinking impure water. And then arsenic to flush out the parasites, which hurts almost as bad as the parasite!

mosquito swarms from standing water
Swarm mobs would be cool. I'm also considering some plant mobs.
alcohol poisoning leading to death or blindness
There has to be some sort of drawback to getting shit faced, do you not agree?
cannibalistic food made from other PCs with FEP based on the stat levels of the dead character
Considered in extensive detail, and some items have already been drawn for it. I've wanted to make it a priority at times. Loftar is a little bit squeamish, but he'll come around.
rodents and insect swarms that decimate crops
Nodnod.
cauldron accidents (I'll leave that to your imagination)
Posted about it.
mines collapsing
... would make mining so much more engaging.
seasonal illnesses
I'm thinking more along the lines of simulated viruses. Spreading via player to player contact, etc. Specific, named illnesses. Theme Hospital was always a great game.
drunken status effects
Yawn, too obvious.
natural disasters that wreak havoc
Too unspecific. Of course, but nut with just any random mechanic.
, dangerous cliffs and winds that push characters off of them
Not randomly, no. That's just boring. Play more Zelda. Rolling boulder objects that have to be actually avoided.
cave adaptation that leads to horrible eyesight
... why didn't I think of that? How is that even possible? Great idea!
animals that can climb over walls and swim through rivers
Well... the fact that they can't handle simple obstacles (shallow water!) is sort of boring, do you not agree?
and a rape toggle.
Criminal acts is already there, right?