One of the problems with being an author - even doing short form - is that writing is a slow process, and you only have so much time. When you work in novel form as I do, then you're talking a major commitment of time/energy/opportunity to any given project. So it's only natural that one would want some clue about which direction to go.
One might think that a sci fi con would be the place to go for the straight word; there are hundreds of enthusiastic readers at even the smallest cons, and rest assured they all have an opinion they will be glad to share. The trouble, though, is that one gets so much feedback, which often is so contradictory, that it can be worse than working in a vacuum. I don't know how many times I've had this happen: I talk to this publisher, and he says this; I talk to that agent, and he says that; I talk to so-and-so bookseller, and he says so-and-so is big now; I go to panels, and they say this-that-the-other. Oy!
And you have to weigh each of these nuggets against the present state of your efforts. For example, I talked with the editor from Pyr at a con not long ago, and he gave me a connection that could get me in with a major New York agent - only the piece we were discussing is in the early stages of writing. Do I abandon everything and press ahead on that? And if I do, will it arrive in time for the contact to still be useful? What about my other projects, including some strategic moves I have been making lately?
It's all so confusing at times. As well-meaning as each of these sources is, it is all but impossible to gain a solid picture of the present market from them. Moreover, no matter how many people you talk to, or stats you review, or editorials you read, it is impossible to predict the future And that is precisely what an author has to do: try to outguess the market a year or two years hence. Feh. The only thing you can do is to depend on your gut instinct about what will sell - not now, but a year from now when your latest opus is complete. So while input from every which way can help you get some sense of the market, you have to make your own choices and hope for the best.