1 - Better swarms. Swarms (even on insane) are too easy to beat, they say shoot the base of a pyramid to knock it down, if you shoot the few dude climbing up on top, they fall, everyone else falls.
Throw a lot more special zombies into the mix, their is a few that appear but not enough to make you panic.
Reduce the amount of time it takes for the swarms to knock down fences and gates, you have to completely ignore the swarm for them to knock the fences down.
2 - More special zombies/Buff the special zombies. Right now they are a joke, when the Bull rushes you hide behind something. when he hits it run behind him , Boom, Boom, two melee hits he's dead. 0_0.
Screamers don't really attract any more zombies that what appear!
Have it so that we cant see screamers automatically, we actually have to find them.
whilst we are searching for them swarms are either doubled or tripled in size. and a load more special zombies appear until the screamer is dealt with.
One head shot and they are dead. pretty much sums them up which sucks.
Have it so when you shoot Gas bags, they start to leak clouds of gas behind them making it a long trail that has been left behind.
Increase their health or even add a helmet under their suit so that they can withstand more than just a single headshot.
Lurkers are to easy.
change up where they can be, it would be interesting to see them on roofs and jumping out of vents at survivors as they walk past.
increase their damage and health a little bit.
To keep the players aware of lurkers, if you added more Skin types to the lurkers so they all are not topless zombies, if they had clothes on and could blend in with the regular zombies, and when you think your ok because the zombies look regular, BAM! lurker pounces on the closest survivor!
Bulls are too Easy to be considered the most dangerous special zombie, I panic more when I see gas bags than bulls.
Give bulls more damage and aggression.
change up their armour so that bullets to the front do next to no damage, the only way to damage them is to either break the visor on the helmet (that needs a major buff) or attack them via the back/sides.
3 - Weapon prestige type system.
I've already got most of the guns to max level, so it have a prestige type of system with different skins that show that you have a gun to a specific level would be cool.
4 - Manual weapon customization.
Its cool that the two levels are their and it shows what type of modifications you can get depending on what gun you select and choose, but it would be good if we got to choose what mods to have on our guns, different sights, laser lights, flash lights, muzzle breaks, silencers all that.
5 - Survivor skins
Having events in the game that allow you to get survivor skins would be cool. just to keep things fresh and interesting.
6 - Base defence mode
To make full use of the swarm mode and keep the game intense, a Base defence mode would be great.
You can use all survivors in the game on the mode. in the mode you will have air drops that help with defences that will break (fences and barbed wire) and defences that run out of ammo (HMG and Mortars). the rewards could be skins for guns or survivors, special mods for specific guns. to keep things interesting you could have quite a large map and you could get distress calls from other survivors (NPCS) that require help, when you finish helping them they give rewards. All that good jazz!
7 - More Classes/Expanding Current Class Trees/Focusing Current Class Trees/Changing Some Classes
Right now the classes skills are all over the shop, I don't know how to explain it fully but if you look at all the classes from level 1 though to level 30. most of the skills they have, have nothing to do with what the class is, the only exception being the slasher class. EXAMPLE look at the medic tree, the first 9 skills are all to do with medical stuff. after that it all spirals down to you kills zombies to HOPFULLY get some items back. Whaaa!
One new class idea me and a friend came up with
Primary - Riot Shield (can be put on back)
Secondary - Machine Pistol
Melee - Baton/Shield Bash (if shield is on back Melee is like it is now, if the shield is in hand, you shove forward stumbling the Zed's and maybe later levels knocking them over)
8 - More guns/Melee weapons
9 - Skills trees for the special weapons/Defence kits (HMG/Mortar)
The special weapons are cool but it would be nice to have like a small level up tree with them to make them slightly better and more effective on harder difficulties. ATM I completely ignore the special weapons.
For the defence kits (HMG/Mortar) it would be nice to either have more ammo better accuracy ECT. and that they come with their own skill trees, so that you can get more ammo, better accuracy.
10 - Zombie corpses
This might be very hard to do, but it would make the game way more interesting, it would be awesome if once a zombie dies, it becomes a static object in the world, even if it means making the corpses look less detailed, it would be cool, because during swarms when killing the pyramids, having the zombies stack up as static objects that can be climbed on and over, will make it way more tense, and increase the threat level of swarms, to the point where they wont need to climb over a fence when they can scramble over a pile of dead Zed's to get to you. Would be Dope!