This reminds me of Unreal's blueprints. You could get a surprising amount of work done just via blueprints and not touch C++ code.

You'd have to balance the input and output connection's granularity - too many would put off users, too few would make users feel restricted. If you manage to find a sweet spot, or let the user pick the level of expertise, and reveal them accordingly, it would be perfect.

I really like how good it looks, and can't wait to use it myself!