Yes, any fighter equipped with those Xenos guns is a force to be reckoned with.
All the more so if it is a light one.
The main advantage of the light fighters is simple: it does not matter whether a projectile that misses you would have barely dented your shield or whether it would have taken out your shield and put a big dent in your armour, as long as it
does miss you. Light fighters can evade enemy fire pretty effectively but heavy fighters and freighters cannot, and so everything that is not a light fighter will get hammered constantly. As a result, you can stick your neck out much farther in a light fighter as long as you don't make any mistakes.
Also, heavy fighters have more difficulty applying their superiour firepower to an enemy because they cannot track them as well as light fighters. For this reason I think a light fighter can do more absolute damage to an enemy fighter than a heavy fighter can in the same time, unless the enemy is very dumb and stays still or flies straight at you.