As a former contract web developer myself, these are excellent points Trevor. You need to find a way for every potential client for every freelancer out there to read this. :) Actionable feedback is so key for working with creative talent in general - we can't read your mind!
We actually built some of these ideas into the core of matchist (http://matchist.com/talent). Specifically, milestones and paying your developer quickly. All projects on matchist are milestone based and the client can pay developers in 2 seconds by just clicking a button.
I can't count the number of times a client has asked me something like "I want my website to be more dynamic. How much would you charge?" I don't know! Why does anyone expect a specific answer to a non-specific question?
This usually turns into multiple back-and-forths to flesh out what the client really needs, and usually requires a lot of thinking on the developer's part (me) to nail down an actionable solution that could potentially be estimated in terms of $$$.
I was hesitant reading Trevor's article thinking what he was suggesting was devaluing dev work, but when he emphasized the importance of specificity I was on board with him. If a client has fully thought out their idea to the point of step by step mockups, that takes a LOT of the pain, frustration, and effort out of the equation which translates to the required work not costing as much.
Developers are one step away from computers (literally) and require a lot of the same rigour when interacting with them. Know what you want and be able to explain what you want (in detail) before engaging them ;)
Why does anyone expect a specific answer to a non-specific question?
The more you can learn to help the client work through ambiguity, rather than expect the client to match your technical understanding and then be frustrated when they don't, the more successful you will be.
"The more you can learn to help the client work through ambiguity..."
This assistance implies expertise beyond just being a code monkey; higher-level thinking and problem-solving should definitely come at a higher price.
Granted, that goes with the territory of being in the service business. My gripe is that clients expect to pay for "just the coding" rather than the entire process of discovery, consultation, and strategy + coding.
We actually built some of these ideas into the core of matchist (http://matchist.com/talent). Specifically, milestones and paying your developer quickly. All projects on matchist are milestone based and the client can pay developers in 2 seconds by just clicking a button.