This is actually analogous to that we teach in User Interface Design 101. There are distinct advantages of showing very early stage prototypes. When we show it

This is actually analogous to that we teach in User Interface Design 101. There are distinct advantages of showing very early stage prototypes. When we show it to potential users they would be perfectly honest about what they don't like. Try it with a very finished product and the users would be polite and not mention the issues they faced. Always, always start with putting a very bad replication of the product in front of your users. Paper prototypes work very well.