I don’t see a problem. 4 Dragonfires already evaporate a cruiser through shields. They don’t miss, are hard to shoot down, and actually invulnerable to PD if they activate behind friendly shield/hull. Imo, they’re only bad when fired from max range or on something that’s about to die anyway.
The only other guided large “strike” missile is Hurricane, and I kinda hate it. It misses, it gets shot down, it’s negated by shields. Even when it hits, against heaviest armor, 1 hurricane is nothing. Its only virtue is being very quick to hit overloaded ships.
Given that I hate Hurricanes and don’t really trust AI with reapers, I’ll gladly fit Dragonfires in large slots if I want burst damage. Haven’t tried medium Dragonfires on not specialised ships, but on missile ships, a few of them work kinda like a perfectly timed, auto-hit sabot + reaper combo.