I think a great example of a good tool set is Blizzards Galaxy Map Editor.
It includes both logical scripting as well as the ability to import custom script code.

As for dealing with Dialogs - a good place to look is Shadow Runs Dialog Tree creation structure. Where it easily allows you to decide the variables on what Dialog to present as well as what options to show based on the requirements which need to be filled by the stats.

Being able to mix the best qualities of these two tool sets would create an incredibly powerful tool for users who are both new content creation as well as professionals who can create wonders with it.