The Vindicator seems very much like it was created to be the standard "do-everything" craft--it's an atmospheric-capable fighter-bomber, not quite nimble enough to be a dedicated fighter but not heavily protected enough to be a dedicated bomber (note the use of "cheaper" Lasers as fore and aft weapons instead of Mass Drivers or Ion or Particle guns, resulting in paradoxically having much less gun power than the Thunderbolt while carrying three torpedoes to the Thud's single). It definitely lends credence to the notion that it was built that way to save money over having separate fighter and bomber models. As for the "special" guns, Pliers himself admits that the Stormfires are his own addition and not standard to the Vindicator, and the Leech guns are some kind of bleeding-edge Border Worlds development. Perhaps the "stock" Vindicator had a second pair of Lasers that were replaced with the Leech guns? A quad Laser / dual Tachyon loadout without the "special" guns added seems like a more balanced fighter-bomber setup.