Its been a while hopefully the grey havens team can return our sleepy friends to us.
http://forums.spiralknights.com/en/node/91698#comment-818375
Slooms are coming back soon r-right guys?
I think just removing the healing aspect and fixing the bugged animation are the only changes needed to it. Then it would just function like a more powerful stun or freeze.
Then the issue becomes just that; it's a stronger version of existing status effects, which makes the existing ones obsolete or less useful.
If Sleep comes back, it needs a gimmick to make it not just "freeze, but better."
Make all the suggestions you want, won't happen until GH gets some more resources.
Couldn't you just stop them from inflicting sleep and add the levels in anyway? Aesthetics seem like a good enough reason.
As much as I want Slooms back, the post you linked was back when Nick was here and SK was in full Swing, Grey havens is still sorting their lives out and things have been going slowly. The best thing to do is be patient and wait for them to tell us what's happening.
They're a freak of nature. *cough cough*
Sleep needs to be fixed first.