I guess you could design without sketching…If you wanted to suck as a designer.

Title: The Messy Art Of UX Sketching
Context: You cannot design without sketching. It just can’t be done. Fact.
Synopsis: The single most important skill – yes SKILL not TALENT – that every designer needs is the ability to communicate effectively through sketches. There is a misguided and erroneous belief that one needs to be blessed with a natural aptitude for artistic rendering in order to sketch their ideas (we are discussing sketching not drawing, and yes there is a difference). This is just misinformed hogwash. Anyone and everyone can sketch, including you. Yes you. Sketching is a skill that does require practice to become effective at but if that seems to be too onerous of a barrier to utilizing sketching in your design repertoire then I would suggest that you are in the wrong business. Designers must iterate and explore and develop ideas quickly and efficiently and sketching is far and away the best tool for this sort of job. Can it be intimidating to sketch for others’ consumption? Sure. But there are techniques and tricks that can be called upon to improve your sketching abilities and I suggest you avail yourself of them. You will be glad that you did.
Best Bit: “I’ve found that others are more receptive to give feedback and make suggestions when shown sketches than when shown print-outs or screenshots.”

via smashingmagazine.com