In D:OS you need to actually learn the script language in and out to write dialog with correct scripting since you don't even get the story-editor style help lines there....

You talking about the syntax guide? It's there just a little more buried. For example if you type:
CONDITION IsLocalFlag(
On the bottom left corner you'll see the order for the arguments.
(Flagname, Bool)
It does require a lot of scripting though for sure. I took a 2 month break from editing and had to relearn it. But I got my first branching dialog with choices and consequences working yesterday. The main thing that annoys me is how the editor doesn't remember string names of flags like it does character and item names.
It took me a solid 2-3 days to learn the basic ins and outs of the editor, but now I'm good to go and I have a campaign in progress.
But I basically agree with this that once you get going it's pretty easy to spit out content. The Caveat to that though is every time I run into something I don't know how to do it massively slows down progress.
it's something modders should be used to.
Modders sure. But for a successful modding community I think new modders are always needed. People passionate about DOS but not necessarily modding. So the tools taking a good chunk of hours to learn is an impediment for those folks. Even if only 1 in 20 were going to stick with it over the long haul.