Who besides you and Henry Ford is participating in this consensus? I'm not trying to be mean or confrontational. The fact that you're speaking of a consensus while sharing the opinions of only two people suggests that you have a lot of additional information you're not telling me about :o)
"Summarized in this quote from Henry Ford: "If I had asked people what they wanted, they would have said faster horses.""
I'm not suggesting that you exclusively pursue the strategy of asking people what they want for the development of your idea. More like guess what they want, then ask them if your guess sounds good. Or listen to a description of what they do now, suggest a change or improvement, and see how they react.
There are two stages to the development of a startup's product description. The first is (or should be) before any code is written. The second is after the initial product is launched. I think you can do both stages effectively without actually being much of a user of the product yourself.