It's funny that so many people have been saying things like this. MLRS, Raiders, Teleport Battlestations, Munitions Boosters, Vorticular Cutlasses, and Deflector Drones all get bonuses against their triangle ship counters. Cutlasses in particular have 64% higher cap bonus DPS than Railclusters, and until recently Fighters only got a 2.4x bonus against them. And Vampire Claws and Eyebots are immune to their would-be triangle ship counters.
Most of the unusual ships, spirecruiser down, are beaten pretty badly by defenses except the vampire claw and eyebots (which
are countered hard by tachyon abilities or a military station)
None of those units are straight up strong ranged combat ships though. The MLRS, raiders, teleport battlestations, eyebots, and deflector drones stat wise aren't that impressive for one reason or another in straight up fleet fights (power creep, non fleetfight specialization, or teleporting). The munition booster has neither the dps nor cap to make it much a threat.
Both the vorticular cutlass and vampire claw are fearsome, but are horribly, horribly impaired if a player kites them.
In addition, none of these ships until the spirecruiser were ultra-low cap craft. The spirecraft's low cap makes its damage decay much less, meaning it gets a very large edge over fighters in cap fights.
The spirecruiser's combination of being a strong ranged combat ship and an ultra-low cap in a fleetfight is what makes it fearsome.