The problem is not that the Callie/Painwerfer rek blobs, it's that they're a two-click squad whiteout tool. Unless you are literally in bed with the RNG god(esse)s, both of these units' barrages will wipe any squad you own off the face of the earth.
The argument that the Painwerfer is fragile and comes in T4, thus it should be able to simply delete whatever it hits, is stupid. You can't even field something comparable unless you field the Callie. Now that the Krapyusha doesn't have its laser-guided barrage, it simply doesn't measure up to either the Painwerfer or Callie in raw destructive power (despite, iirc, equal expense to the former and despite also being locked behind a T4 that is now impossible to skip to, barring the T1/T2 choice).
I'd up the Callie's default range by maybe 25, slap ~2.5º higher scatter on it, and give it a continuous barrage, not this silly burst rocket nonsense. You can use the tank-like HP to drive it into sword-hitting range or hang back and hope a lucky rocket lands on your intended target. The large(r) scatter value would also help it put the hurt on larger blobs.
well said.