I think what you have is great and I think you should run with what people are seeing this as "awesome" for, design prototyping. I think making this into anything that generates layout or uses the browser engine is going to be either: much harder than you think, or: will lose much of the functionality that you can allow for now via "do whatever, drag/drop, absolute positioning".
I totally agree. I've been wanting an app like this for the last 6 months (wondering why one didnt already exist), and a lack of fluid layout doesnt put me off at all. The one thing I really want is realtime collaborative use, ala google docs (Firebase should make that easy).
