Bill Buxton has given us a language to talk about Design and various stages. He has introduced the distinction between getting the right design and getting the design right
Buxton has also talked a lot about hand drawings and sketches. Per his yellow book the difference between a sketch and a prototype is not the fidelity but the intention and what it communicates. I personally talk about it as describing "what could be" vs. "what should be".
I think however that there is a tendency to grasp on to the notion of hand drawings (or finger paint as I heard in one presentation (sic.)) and talk about it as if the are the solution to all early design thinking. I would suggest that they are not. Different problems need different solutions and fidelity does not equal done-ness
I am all for doing the right thing given the phase of the project and the problem at hand. But I am very much against lack of critical thinking and dogmatism. Communicating something through a hand drawing does not make it a sketch. I know people who can draw rectangles and scribbles but at the exact relative size so they can make very precise specifications for placement by hand and I know people who can express crazy far out ideas pixel perfectly.