Prototyping is a different discipline from traditional software development: less architecture; more speed. Get the key features out there and see if people bite. Only go back and fill out the parts of the product, business or system that the customer has shown an appetite for.
That’s how some of the best technology companies in the world work (ever noticed how almost all of Google’s products are in beta?). It’s the way we build our own products and we’d love to discuss helping you do the same.