You know what they say VietReefer - it's not the size of the rod.......it's how you use it.
Seriously though, That day I was using 2 lb mono cuz it's softer and tangles less, on a 7 ft Berkley Tactix trout rod. The rod, line and lure weight are matched, and we were throwing straight 1/32 oz mini jigs that day. I can cast significantly further with 2lb line vs 4 lb line on this setup. If I really want distance I add a small clear casting bubble float completely filled with water.