I really love the idea but I'm not sure about the presentation. I'm not sure about using nodes to do that, as someone who manage that in his game in a text file. Maybe linked boxes like visual script ? I'm not into that either but it allows to see everything at one. With a node tree system, you have to click on the node to see its content.
Altough, using the node tree something I like generally. I made my plugin with custom nodes too (feel free to check it :) ). I feel like it's more appropriate some times than others.
But good work, it looks very complete and well done, I wish there was an actual demo scene tho.