But I believe that a guy who can sketch at least to an approximate scale can visualize the entire interface with just a sufficient level of detail. Unlike this, a doodler might get the big picture, but would - in my view, still need a sketcher to fill in details.
Also, though not necessary, being unafraid of number crunching and having the ability to sit with end users and patiently observe their interaction will probably be an added advantage.
OK
UI designs need to be accurate and complete to be any use. A doodle is neither accurate nor complete. I have designed UIs, and I would simply not waste my time looking input from someone who cannot do a proper design document.
