Sleep

This will be pretty straightforward:
So, everybody knows that once upon a time we had the sleep lichens and now we're stuck with armors and trinkets that have sleep resistance, but no situation that would beneft from it. The big suggestion becomes obvious: make sleep monsters and so on and plan a comeback for things like the sleep lichen.
Sleep monsters can make new fun stratums and so on, you might make it a boss, whatever, make the res. usefull! Than with those sleepymonsters you can create some gun/sword/misty bomb that induces sleep. This will make that resistance usefull, you get people farming and rejoicing over a new weapon and aspect in the game, and heck whynaut, you could even make a expansion mission pack solely based of sleep from it!
There, problem solved. No more lying around statistics that would never be used and another new goal for veteran and new players, including some means to experiment with and discover new stuff.
Any objections?
(And while you're at it, bring back the Vogs who have armor and weapons but aren't even ingame)

The amount of trolling this boss could potentially do sounds delightful (i.e. Putting whole party to sleep, then wander aimlessly). Would be interesting though, bring something fresh to the game.

I made a list of names for sleep-themed enemies, but that seems to have been lost in the depths of the forums.
From the ones I remember:
Narcolisk (Chromalisk)
Lax Knight (Mecha Knight)
Dirt Nappers (Zombie)
Slackilite (Devilite)
Diamond Greaver (Greaver)
Sleepy Hollow (Lumber)
Tranquibot (Scuttlebot)
Naptrode (Retrode)

There have been plenty of great suggestions for Sleep enemies, but there are problems with this.
Being inflicted with sleep has two problems:
1): You heal (Should be easy to fix).
2): To quote Juances (I think) from an earlier post, "all you can do is yell at the screen and throw your keyboard across the room." You're incapable of doing ANYTHING while asleep. Freeze is already annoying, but you can at least attack. Being put to sleep constantly would be a serious pain.
~Sev

Well, to hook up on what Severage said:
while you sleep you heal. I don't really see how thats bad (for you at least), making a death due to chainsleeping hard and maybe even unprobable. Also, as with freeze it might be convenient to make your partners able to snap you of it. Something like reviving, but instead you shake em up.
Also chainsleeping can be easily stopped by making not every single attack sleep-inducing. Problem solved, right?
(and i like those sleepynames)

That's would be interesting. This would make Purfect Katnip Pouch trinket usefull. Three Rings, please.. If you want to remove Sleep from the game, please just remove The Purfect Katnip Pouch trinket and replace Royal Jelly Set Sleep resistance with other status effect. But if you want to fix it, we will waiting.

@Wenkuang
If those names aren't a Siren call to Nick, I don't know what else would do it.
Why do people seem to think that if the game can't be changed to where if you're hit, you wake up? Even if it's a sleep inducing attack to remove the risk of chain sleeping?

I don't think being chainsleeped would be any more better or worse than being chainstunned or chainshocked. If anything, at least being attacked would remove the status (unless it's applied again), and maybe heal if you're left alone for a bit; though I could see this breaking gameplay a bit with the healing function, considering you could just let enemies put you to sleep on purpose, then have your allies keep it from you while you heal.
I dunno, it seems like a possibility, but there was probably a good reason why those enemies were removed for now. Perhaps they'll put them back in once they've figured out how to balance the status effect.

To add Sleep back in would require overhauling the mechanics for it entirely.
Maybe make sleep based less on actual sleeping, and more on sleepwalking? As in, you get hit, and your movement is slowed down (probably a bit faster than stun's speed reduction), and you are still able to move around, but your controls are distorted, reversed, something. Might be kinda hard to program, since we can choose our own keys, though.

One of the problems with Sleep is that the mechanics make soloing impossible. Soloing always has to be an option.
Sleep resistance hasn't been removed from the game because OOO has every intention of using it. It is very difficult finding a solution to this problem because you also have to account for the possibility of Sleep inducing weapons for Lockdown.

What Alchemystic said = what was going to be my response to Floipd.
I almost never, ever do PvE with a party. Only during Vanaduke runs do I bother to get one. Getting chainsleeped would make it impossible to proceed.
~Sev

simple,make it so you dont heal when put asleep.and as for the inability to do anything,make it so where when your asleep you have to spam the attack button to wake up,or,as they said,make it so that more enemy attacks would wake you up.

Implementing sleep, plus other mental status effect ideas
The main problem I see with my idea is the potential for the temporary invulnerability to be taken advantage of, but that's far better than any kind of healing. There could even be enemies with special attacks that damage sleeping targets. If this was programmed in, the z pattern for sleep could also be used to indicate when a downed knight has already been given health so you don't have every player running over trying to help.
-espil

Well, the idea of Espil to make sleeping like a revive that otherwise weares of after a certain period (like with all statuses) would finish of the other problems described. The healing part still is somthing that could be left in, or when going for the revive-like way of dealing, healing would be enemy-exclusive since a player has the invulnerability instead of healing.
an expansion mission pack?no.the last expansion mission went over like fecal matter in a punch bowl.
But as for bringing back sleep?Yes.please.I BEG OF YOU OOO!!!!it would be something relatively new and challenging.i suggest:
1.bring back slooms(which cannot spawn in the monster box-things anymore)
2.bring back sloombargos.
3.bring back the shrine of slumber.
4.make a sleep boss?it would definitely be interesting.
and.......thats all ive got.well,theres my two-cense worth.