I took a couple screenshots in Q4 to show what people expect from widescreen view.

http://home.comcast.net/~richeyk/quake4_comparison.jpg

These were taken at 1280x1024 (5:4) and 1280x720 (16:9) at the default 90 FOV. Nothing is lost when switching to the 16:9 view, instead the horizontal view is increased as expected.