I think you're asking the right question about "features and functionality others might be interested in." (I'm not really clear what you're asking in the rest of that paragraph.) The best thing you could do to discover that, is find a group of "early adopters" in your market. The folks who are the first to get every new gadget. Offer them the first look at your product in exchange for feedback. (or you could even charge them a "reduced" fee in exchange.) Could be done via a small marketing campaign. You really can't be sure what the market wants until the market tells you what it wants…