@IchoTolot: You wouldn't have to copy it over and over - just once .

That's how it all starts.

Ghosts, however, have very clearly defined uses and limitations

I'd also make the case that disarmers are less intuitive than ghosts

I know that ghosts can fly so I expect these ghosts to also fly around the map. Ghosts are far far far away from being intuitive.

Also I see the object ignoring not really valuable, there are enough substitutes for it as well. The fear part would be the only thing remotely interesting, but it can lead to very fiddly stuff, which I don't like.

may I remind you of features that got removed from Old to New Formats that are now being considered for reintroduction

All the cases you mentioned here, came together under vastly different circumstances than the big gimmick cull.

Back then we all actively discussed and decided to remove gimmicks.

All features you mentioned here are casualties to the great tool switch.

Backstory:
Nepster created a personal editor for himself back then. When the new formats came along, this freshly built editor, which was mostly built around Nepster's level creation needs, became the base for the new editor. In the next months we gave a ton of feedback for this editor to make it more generally accepted.
The way of inserting terrain was one of the most criticised things about the old editor, so this one took another route.

The toolkits had to be coded from skretch, so things like the "replace" button never were actively culled, they were just forgotten/overlooked.

While only the first assignment should be applied, the others should be queued instead of being ignored.

Totally fine with that.

I solved a certain old format contest level exploiting this behavior. This is still possible in new format NL though as the replay format didn't change.

Reproducing:

- Load a level.
- Assign a skill to a lemming.
- Assign a 2nd skill on the very next frame (for simplicity purposes) to another Lemming.
- Save the replay.
- Close NL and open the replay file with a texteditor.
- Look at the 2 skills assigned and change the frame of the 2nd skill to the frame of the first, while updating the 2nd Lemming's position to the position the Lemming had on the frame before:

Example:

Original file:

$ASSIGNMENT
  FRAME 85
  LEM_INDEX 1
  LEM_X 111
  LEM_Y 135
  LEM_DIR left
  ACTION builder
$END

$ASSIGNMENT
  FRAME 86
  LEM_INDEX 0
  LEM_X 209
  LEM_Y 151
  LEM_DIR right
  ACTION basher
$END

After editing:

$ASSIGNMENT
  FRAME 85
  LEM_INDEX 1
  LEM_X 111
  LEM_Y 135
  LEM_DIR left
  ACTION builder
$END

$ASSIGNMENT
  FRAME 85
  LEM_INDEX 0
  LEM_X 208
  LEM_Y 151
  LEM_DIR right
  ACTION basher
$END

(I've attached an example file where the first 2 assignments are a double assign)

NL will accept and load the edited file and assign both skills in the same frame to their respective Lemmings.

Fix proposal:

If we have multiple assignments in the same frame in a replay file: Only execute the first assignment, while all other assignments in the same frame will be ignored.

This fix will therefore trigger no NL error and it won't be noticable. This is only discovered anyways if a user deliberatly edits a replay file to do this, as double assignments are otherwise forbidden in the player.

causing the occasional lemming to fall through a trampoline and die.

There is the rule that trampolines only can handle 1 lemming at a time (at least I think), like a fast trap that can only handle up to a certain density of lemmings before letting some past. That is also the reason why you can have problems on Sport 1 getting a gold standard.

I've found 2 possible solutions. One is quite timing dependent though.

Maybe this is more likely to be intended.

The new update wasn't released yet. So the change still needs to be implemented.