Summary of the rest of this post: Although Simon's cull-o-mania is too much for my taste, I still think that the oddtabling option can be removed completely, because it is barely ever used and its effect can be reproduced by standard editor actions.
...it might be best to leave it until a time when there's a major overhaul of how things work.
Once the level files are stored in a more accessible way, oddtabling becomes superfluous anyway. Then one can just copy the header with all the level stats from one level file into the other. No need for any oddtabling option in the editor any more.
Under the current structure, there are VERY obvious reasons why filename is not an option. This could of course change in the future.
Sorry, but I do not see the "VERY obvious reasons": The toolkit (or rather the system.dat) already has the names of the level files and their location to load them when creating the .nxp. So I see no reason why one cannot use it for oddtabling purposes as well. Of course once creating the .nxp, this info has to be translated e.g. to the current oddtabling references, but there is no need to do this already in an earlier step.
Perhaps, one other acceptable workaround might be to add a feature to the editor to load the layout / etc (anything that oddtabling copies) from another level, while leaving the things it doesn't copy unchanged from the current level. While not quite as convenient (once all else is working) as oddtabling, it would still improve the copying of layouts between levels compared to not having any features aimed towards it at all.
This would be an improvement, because it is much more stable, allows for playtesting levels in the editor and its effect is much more self-evident to new level designers. However you really should think hard about whether this option is needed at all. Although it has some some uses, they still are very limited. So I fear that (similar to oddtabling) this option will hardly ever be used. Does this really outweight the disadvantage of making the editor more complicated?
Looking at my own habits in using software in general, I see the following: Whenever I need to do something new, the first thoughts are always "How can I do this with the options I regularly use and know where to find?" Only when something turns out to be very difficult or outright impossible with them, I look whether there are new options I could use.
Applying this to the NeoLemmix Editor: The standard actions
loading and saving levels together with
changing level stats does precisely the job that oddtabling/load only terrain does as well. So it is very unlikely that I will ever use this.
This brings me to a last question: Does anyone (DynaLem, GigaLem, ...) currently working on a NeoLemmix level pack plan to use oddtabling or would you use the load only terrain option?