I agree with it really depends. Lots of brush calls for heavier denier (and heavier overall weight) rain gear; lots of heavy rain typically calls for stouter (heavier) rain gear. In the mountain west our rain typically is sudden, but generally doesn't last very long- for these conditions I use the lightest weight 3 layer rain gear available.
For lighter rain/drizzle/wet snow I prefer using a windshirt on the move over a rain jacket. It has enough water resistance (in the 300 HH range), but has many times the breathability (~20-40 cfm) of any rain jacket.
The military's clothing system has adapted the same strategy- they only call for using rain gear when they are stationary- on the move they utilize a water resistant windshirt or softshell.
