I really like this - having movement definition sets is an elegant way to make it support different movement types. I could see a tool like this being handy for making a platformer, or even a tile based puzzle game (like a sokoban-like) if your search could include state changes for multiple entities. Ideally you'd support loading/saving TMX tilemaps.
I'm not in the market for a tool like this right now, but it would've been useful for me in the past - if anyone uses it for a project it would be nice to know how they get on with it, then you could know if it's worth expanding into a fully featured product.