Clients will always have a solution in mind when they are approaching a service provider. Most of the time they cannot fathom paying someone else a significant amount of money if they have not came to the conclusion that they need a “web site” or a “new interface.”
Step one is to get a level above their thinking. Get to their actual problem. Have them talk about the reasoning they were thinking about behind their decision.
Then use that information to solve the problem. If your conclusion is different, then you want to have that conversation right away. An unhappy client without a business is a problem for them and yourself.
There are lots of web sites that chronicle the “clients from hell”. But what about the designer or developer that doesn’t say “no”? I bet that list would be a lot longer.
So how do you combat such predicaments? Find out what is the most valuable minimum viable product that is valuable to the potential user. No matter how much heroic programming or designing goes on in the background - if you can’t produce value for the user, it helps no one. Raking up billable hours for your client without increased value to the client does nothing but reduce your value. Keeping your value high as a contractor, as well as the value of the product - needs to be a team effort between yourself and the stakeholders in the project. Remember everyone owns everything in the beginning. Thinking any differently otherwise is sabotage, and will provide less to your users.
Find one use case and build for it. Build one thing at a time. Put it in front of your users immediately. It won’t be perfect - actually it will probably be pretty shitty at first. I bet you will hear a lot of different perspectives that you would have never thought of before. Use the feedback as motivation and inspiration to make the product better. Be sure to do usability testing and have some outsiders that you pay or trust to give you good feedback. Remember a sample size of one helps nobody.
Perception is reality. It helps to have a user representative that is in the same office but is not involved in the day to day development of the application. You do not need the mental baggage of how long something took to develop. You need objective and emotional feedback from someone who just uses it - like the user. In short, users are the key to any successful online application - so why not have one or two desks down, and develop for him or her.