I would love to see a flow chart option. I know its not the same as SQL DB, but when doing software design and planning we use flowcharts for organizing the program flow / decisions trees / user interface etc... They sit right along side our DB development, often side by side, one informing the development of the other. Based on your engine it should be simple to add a basic flowcharting function to your system. (Heck we can fake it now almost with tables and relationships). We currently use Draw.io, but your pure cloud based, team approach would be better.
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