I was on a UA flight from DTW to DEN and was listening to that channel. We were told on the PA there would be a delay because of weather en route. After, on CH 9, the pilot suggested an alternative, more northerly route that he felt would be better. The ATC responded that no one else had thought of that and he should give it a try. We arrived on time while everyone else was delayed. He never explained it on the PA system, but I felt we were let in on what an experienced and thoughful crew can accomplish - we never would have known it. I thanked him as I left the plane. It was a particularly nice trip for that reason.