Looks cool, would be a lot more interesting to me, if it included data io with postgres database functions and views.
I never use direct to table updates.
Being able to easily created a web front end to a database with a tool like yours, would be extremely useful to me and I would happily pay for such.
There are umpteen tools for creating schemas and managing databases - most like PgAdmin are pretty poor - I use Sublime Text. Unfortunately there are no RAD tools available for creating simple UI's. All my logic is in the db so I just need simple forms and display grids. I had a quick look at Envelope but complexity of setup and poor documentation put me off.