I think Frost may need an adjustment pass. Fill a Heron with 3x Frost and watch it tear into an Astral. It easily beats Spark, Khophesh, Warthog or any other fighter or bomber I've tried in both anti-fighter and anti-ship roles. Its 'shotgun' is obscenely powerful and chews through armor fast. They also die rarely, but I think that has mostly to do with them being so good at killing threats quickly rather than any defensive stat.
YMMV, but to me there's an issue when I put Frosts in every fighter slot and just ditch the bombers and more expensive craft cause I don't need 'em.