There is another way to look at this as well. No not EVERY single player plays slow, but in my experience a more than acceptable amount do. Including myself, if there is no timer on the tourney, I guarantee I will take forever on nearly every word and second guess myself and relook at things to see if I can get a better, longer, higher value word. The timer has actually helped keep me on my toes, makes me think harder and faster and has actually made me a better player in the long run.
I can also see getting easily frustrated and nervous knowing your timer is ticking away, but just trying to throw out another way of looking at things.