I have many ideas and I posted them in Steam forums but there may be small interest from developing team so I wanted to post my thoughts on official techland forum too.
Some ideas may be to hard for casual game type but I hope there is possibility to make extra difficulty or option that we can check to any diffilulty like in Fallout 4 with its survival mode. Or option in game to add mods but it would require more access to game files. More than DL had becasue many things sadly cannot be changed/tweaked/moded.
1 - Climb down option. Pointing view at edge should give option to climb down. Or maybe turning back to edge and moving back could initiate edge grab while fall.
2 - Dificulty extra options and hud options. Options that can give extra options to tweak. In there option to disable icons showing enemies like volatile icon of them start to seeing/recognozing me and those yelow annoying eye icons showing that some zombie is changing.... I can see by animations that he is changing and hear so why forcing me to see also some indicatorson hud? Same for volatiles that I can hear so I know that I am in their field of view so I do not need icons and cones on radar etc. Would be cool to have abilityy to disable those handicaps. I remember in I think FarCry 4 option to disable enemy sight sense so disabling such handicaps would be cool.
Also difficulty settings where player is not like some god that can see through walls using some weird mutant bat ability. Difficulty that make game more immerse instead only difficulties for casual players.
3 - Modding ability. As I am sure I will need to tweak many things like handicaps for casual players. I want more in deepth settings in files that can be modded. It would be awesome to be able to create own unique experience instead of difficulties that are made for average casual player. Also in game menu mods section for easy mod loading.
4 - Body inertia/momentum. As I was able to mod character movement and add inertia and momentum and now in DL I feel more like a human instead of as in arcade games a cardboard box there is still one problem... Turning 180 degrees without slowing down! It gives opportunities to sprint at enemy, hit him and on a dime make 180 degrees turn and run back away from him with. It is making fighting with giant zombie with almost no problem. Sometimes giant is able to make attack that surprises me and this recompensate this awful typical casual FPS game design of 180 turn while sprinting/running and not lose any momentum because there is no inertia in arcade games making them to easy to play.
5 - Harder gather things.
-Reduced loot (good that in DL1 it was possible to tweak through files).
-No distance spawning plants! They spawn back if player goes away about 50meters! They should be timer based respawn! For example 48hours! Good if that would be modable in files.
-Weapons in trash containers also spawn back!!!
6 - Saving only in safe houses. At least on hard and higher difficulties. Game is sandbox, open world so player should decide where he want to spawn after loading game so he dont need to travel back like stupid to last place he was exploring. There should be some object to use to make save point! Not bed as it is for skipping day/night.
7 - Time pass after death. After being killed there should pass some time for example from 3 to 6 hours. That way instead of magic teleport it would simulate that someone recovered us from where we collapsed. Also it would be cool to have animation to get into a bed and get out from the bed. That way after we would be defeated in the field we would wake up in closest safe house.
8 - Checking hour. Add keybind for checking a watch for hour. In DL it required downloading a mod.
9 - Night were good in DL. Do not change how night was made in DL. I mean do not make it brighter and change shadows ETC. I love sitting in the dark and avoiding volatiles and waiting for my health to regen as I moded rate of HP regen. I do not like to cheat so I dont have them shown on minimap at all by my mod tweaks so this makes night time way much scary and I love pitchblack places. It is very realistic.
10 - Survival mode! Similar to what Fallout 4 did.
Extra option to have survival needs like water and food and maybe some diseases like common cold When you run in rain for to long and do not have proper body cover.
In trailer there is fight over water resourcess. In such scenarios as post apocalypse or pandemic there is need for such things as water and food so fighting for such resourcess will add challenge for those who want it. In this days lots of people like such gameplay features.
11 - Add switches to rooms. Ability to turn off and on light and this way hide from basic type of zombies. Also cool thing to have in game that give more immersion. I just read note 11 found in building near power field. This gave me extra idea of side quest to switch off as many lights left on by those who became a zombie.
12 - Fatigue system. Longer constant running over and over again should create fatigue. It could be removed by sleep, sitting on comfy furniture or slightly reduced by drinking this famous pricy coffe
13 - Ability to use chairs, sofas etc. It would help in removing fatigue.
14 - Bad odor. There is lots of things mostly like decomposing bodies in zombie apocalypse. Our character in any game is so damn chill about roting bodies ETC.
Bad odor should reduce our breathing abilities to about 40-50% because of this foul smell. In real life it is hard to sustain such foul odors so we hold breath, try to do shallow inhales ETC. At least normal human does that and decomposing meat is very awful smell and I dont know anybody who could sustain longer period of time in place with such bad odor. So in game to prewent losing stamina we could use some masks to cover our haces. I don't mean gas masks but those could be also implemented. Normal masks would have ability to reduce stamina loss percentage. Also we could have skill to unlock that would reduce this stamina loss. Less stamina less swings! So it would be good choice in skills.
In DL we had so many free space in skill trees so it would be more interesting to have more skills to chose from.
15 - Movement physics similar to GTA5
Walking in water more immersive and moving uphill slow down character and moving down sliding.
16 - No stamina free activity In DL there was kick totally for free. It is one of things that breaks immersion. In files kick stamina was 0. I changed this for my liking but it would be cool to see DL2 with more logic and smart design.
17 - Upgredeable/buyable flashlight. Battery change and quality In DL on normal mode flash light had unlimited energy which sucks. On Hard it had limited energy which was more immerse. But why not making flashlight work in more smart way? Maybe battery change option? We could find batteries and swap them if our flash light would start to lose energy? Maybe more types of flashlights? Some weak ones, medium ones and better ones? All would differentiate through themselves by cone radious and energy consumption? Batteries would be better brands or cheap brands differentiate in stored power.