sort of off topic but could you describe this cap you're referring to?
In Warcraft 3, the total AOE damage possible by a single source is capped at a certain number.
What I'm suggesting is that AOE damage should be capped per SQUAD.
Example : A Conscript has 6 models of 80 hp each, making it 480 hp. But if the models are clumped, a single 80 damage grenade will wipe it. Lets say we cap the grenade damage to 300. Even if the models are very close, at least 2 would survive. Or maybe 3 would survive with less hp on each model. Calculation can vary, but you get the idea.
If it was a grenadier squad, with effective health of 320, would probably leave a single model with 20 hp by the 80 damage grenade.
Of course this is capped by squad, so if a single shell/grenade hits multiple squads it should deal damage to both squads without being capped.
It might take a step back from realism but with appropriate numbers it shouldn't be that bad, and make the game less prone to RNG-induced stress without touching the anti-blobbing power of AOE weaponry.