I see the Echo as lowering the checks on the party more than anything. But it cannot save a party that does not know the mechanics of the fight. Have full echo bonus? Too bad, because people don't know how to dodge the 1-shot mechanics, they die anyway. As I've said time and time again, the Echo does not help those who do not know the mechanics. This is the intended flaw of the Echo, it cannot nor will allow those who don't know the mechanics to pass the fight.