Daec

it would be very realistic if the only way to communicate to your friend in pz from long distances is if you had a walkie talkie.
 
or if you wanted to text you would have to find a phone.
 
you could still talk to your friend if your near.
 
of course this also would be an option for realism.

I wonder why multiplayer is the must have feature. To me it would be more of a "nice to have". But only to play coop with my friend. To be honest, in these type of games (survival). Other players are more like a gamebreaking thing to me. Thats not because im carebearing, but because most players turn out to be utterly stupid a******* (the Kind of people, kicking little children's sandcastles at the beach or stealing candy from babies).
Just look at already existing multiplayer survival sandbox games. Most of the players seem to only have the goal to ruin other peoples game. DayZ beeing the top notch where the only interaction between players consist of torture and murder 98% of the time.
So to me this doesn't seem like the Road to success.

I wonder why multiplayer is the must have feature. To me it would be more of a "nice to have". But only to play coop with my friend. To be honest, in these type of games (survival). Other players are more like a gamebreaking thing to me. Thats not because im carebearing, but because most players turn out to be utterly stupid a******* (the Kind of people, kicking little children's sandcastles at the beach or stealing candy from babies).
Just look at already existing multiplayer survival sandbox games. Most of the players seem to only have the goal to ruin other peoples game. DayZ beeing the top notch where the only interaction between players consist of torture and murder 98% of the time.
So to me this doesn't seem like the Road to success.

You already have something similar with the meta game. Just survive long enough and there'll be a chopper flying over your safehouse, drawing the attention of many zombies into you direction. Or a gunshot near your position, ringing the dinnerbell for your neighbourhood. With NPCs there could be a group or a single NPC fleeing a horde right into your direction. I guess if the migration system FJ45 mentioned is worked out, you'll have your thrill. Just give it some time

You already have something similar with the meta game. Just survive long enough and there'll be a chopper flying over your safehouse, drawing the attention of many zombies into you direction. Or a gunshot near your position, ringing the dinnerbell for your neighbourhood. With NPCs there could be a group or a single NPC fleeing a horde right into your direction. I guess if the migration system FJ45 mentioned is worked out, you'll have your thrill. Just give it some time

I think randomness would definitly make it a "hate" mechanic. Just like you said, people should know why they fell. Latest point beeing after they fell. Just like "god damn it why did i break my ne...oh there's a bloody corpse on top of the staircase i tripped over while backing there...damn it why didn't i listen to the guy brabbeling about not fighting on stairs?" .
No seriously i guess with the threshold there only should be clear falls. Like sprinting across wet grass in the rain, tripping over a corpse in the high grass. Thats something pretty logical. With slippery ground, bad vision because of heavy rain an a not so good placed corpse in the tall grass thats hard to see aswell.
On the side of the "taking it out of control of the player" part...a "push f to fall" function would be pretty useless i guess. Falls are out of control, otherwise you wouldn't fall.
Maybe if this would really work, like falling down the stairs could be a neat thing for dead bodies to implement. Cause a dead bodie mostly handles stairs at what it is. A 45 degree slope with bumps to gain momentum. So a zombie slain or pushed on some stairs would fall down, inflicting damage and possibility to fall for anyone downstairs. To teach you or the zombies to NOT FIGHT ON STAIRS DAMNIT!

What's always the matter with "special zombies". They are the most immersion (and therefore in this case game-)breaking thing i know. It makes me roll eyes at resident evil and makes me stop playing L4D after one round. A big fat zombie running around puking on people or "blowing himself up????" Instead of eating their brains? Dafuq o.O?!? Why should raising from the dead grow my tongue 10m long? Must've been helluva ladiesman in his living. Why spit acid? Zombies are flesh and bone too so they would be a puddle before even trying to. Every concept of "special infected" already sounds silly. Im not meaning to be rude.
The only thing plausible would be "small" variations in speed, strength and health just like with normal people (that they were before). And maybe im mistaking but i guess thats already there.