I think it'd be interesting, for one. It would give modders a good idea of what the whole experience is like. And yeah, it can be a little tedious sometimes, quite often even, but anyone serious about modding will realize that. Anyone you'll discourage with "boring videos" is almost certainly not going to mod anyway. And I imagine people experienced with the editor can actually do things reasonably fast.
Spoilers are a concern, sure, but there must be some little side quest you could work on that wouldn't be too big of a deal to show some stuff for. Unless, of course, it's in a brand new zone or something.
I reaaaallly want to see the new dialog editor. And proficient terraining would be interesting. Scripting a quest would probably be the hardest thing to demonstrate without 99% of people's eyes glazing over, but some people would like it.
