I do agree Pathfinder is badly designed. JLI & pathfinder shouldn't have existed. insta kill is too powerful mechanism in the hands of moral. I bet BT never dreamed of 4 barfinder spamming.
Pathfinders have no "insta kill". The closest thing is their critical shot on models who have 24hp or less. The DPS on their snipers was nerfed too. Last I remember they dealt 16 damage on a hit, doubling to 24 for the crit, now it's just 10 damage on hit. I think the crit works the same though. Same for JLI but their crit threshold is like 60% hp or something.
Either way, a deathblob of units focusing one squad kills quickly anyways. 4 obers/ shocks/ LMG grens is going to shred too.