In addition to that, their masterwork properties change the way you use them drastically (On top of that, you can add triple gun sigils to increase the damage by 90%)
For example, the blastback heavy pistol does triple damage when hovering. If you combine that with different javelins:
- The Storm can boost its weakpoint damage while hovering with the gunslinger's mark component, and is the king of hovering
- The Ranger can boost its hovertime significanlty with 2 components, and has abilities boost its gun damage by 210% easily (Venom Darts + Muster Point + epic component)
- The interceptor can use both target beacon and a class specific component to boost its damage by 210% as well (acid bomb + target beacon + epic component)
Another example is the elemental rage, that boost elemental damage on hits to elites: Imagine a Ice Storm / Burning Orb Storm, or a Lightning Coil / Flamethrower colossus with that gun in their hands
Or we can even take the beloved devastator sniper rifle: Again, the ranger and interceptor can double their gun damage easily, but on top of that the ranger has components that boost blast damage by 50% (and bast damage boost comes on inscriptions as well).
I agree that the guns aren't the focus on the gameplay, but each javelin definitely has ways were they get ridiculously powerful when you interweave gun damage with abilities. All the example I gave above were with epic components, save for the gunslinger storm, so that is just the tip of the iceberg.