I look forward to getting inside the editor in the future. I had a go for a brief moment but couldn't switch it to renedered view so at least I can see the textures (perhaps it's meant to be this way).
Referring to the above discussion my notion of a modder is: a person who "modifies" (elaborates upon / extends) already incorporated assets as opposed to a game designer who makes his own from scratch.
Ultimately one couldn't claim copyright for the things one created with Reverie's because one wouldn't be using one's own assets and one's own engine and that disqualifies one from calling oneself a game designer / dev (unless one pays royalties like with Unity3d or CryEngine), but you could claim you incorpotated your own elements in your scenarios like code, individual assets therefore "modding" is the right word.
That said it doesn't stop me from having fun with the editor especially if there's a prize for using it